MergedFile

M-STEP VERSION 3


STEP- II



DIESEL COMMON RAIL





TRAINEES' TEXTBOOK












































MMMTC Ver 1

<Common Rail Fuel



Injection System>

CONTENTS


<Common Rail Fuel Injection System>

1. GENERAL ------------------------------------------------------------ 1-1 / 1-5
(1) System Block Diagram
(2) Control System Diagram
(3) List of Components and Functions
(4) Knowledge Check

2. SYSTEM COMPONENTS ---------------------------------------- 2-1 / 2-14
(1) Location of Components
(2) Engine-ECU
(3) Sensor
(4) Actuator
(5) Knowledge Check

3. SYSTEM OPERATIONS ------------------------------------------ 3-1 / 3-12
(1) Fuel Injection Amount Control
(2) Fuel Injection Timing Control
(3) Fuel Pressure Control
(4) Idle Speed Control
(5) Throttle Valve Opening Control
(6) Power Supply Control
(7) A/C Relay Control
(8) Condenser Fan relay Control
(9) Emission Control (EGR System)
(10) Glow Plug Relay/ Glow Indicator Lamp Controls
(11) Knowledge Check

4. CONTROLLER AREA NETWORK (CAN) ------------------- 4-1 / 4-4
(1) General
(2) Structure
(3) System Operation
(4) Voltage Transformation on the CAN Bus
(5) Self-Diagnosis
(6) CAN Bus Diagnostics
(7) Knowledge Check

5. DIAGNOSIS SYSTEM --------------------------------------------- 5-1 / 5-9
(1) Freeze-Frame Data
(2) Diagnosis Code
(3) Data List Function
(4) Actuator Test Function

6. ON-VEHICLE INSPECTION AND SERVICE ---------------- 6-1 / 6-11
(1) Required Service Operation
(2) Chassis Number Writing
(3) Ignition Key ID Registration
(4) Injector ID Code Registration
(5) Small Injection Quantity Learning
(6) Supply Pump Correction Learning

1. GENERAL


1. SYSTEM BLOCK DIAGRAM
The common rail fuel injection is an electronic controlled system that consist of sensors, an Electron-
ic Control Unit (ECU), and actuators. Sensors are devices that convert operational conditions of the
engine into electrical signals. The ECU processes these input signals to produce an output signal
that corresponds to the operation conditions. The actuators are devices that will convert the electrical
signals into the elements of delivery that will cause the engine to properly operate. The Engine-ECU
controls the fuel injection, the boost pressure and the exhaust gas recirculation (EGR) controls. In
addition, the Engine-ECU contains a self-diagnosis system to facilitate in diagnosis and repairs.































































Fig. 1-1














1 - 1 Pub. No. PTAE1228

1. GENERAL


2. CONTROL SYSTEM DIAGRAM





































































Fig. 1-2



















Pub. No. PTAE1228 1 - 2

1. GENERAL


3. LIST OF COMPONENTS AND FUNCTIONS
Name Function
Engine-ECU Manages the control to actuate the actuators in accordance with the driving
ECU
conditions, based on the input signals from the sensors.
Ignition switch-IG The Engine ECU uses the ignition switch-IG ON/OFF signals to initiate or
terminate the control activity, and to turn the engine control relay ON/OFF
accordingly.
Ignition switch-ST When the engine is cranking the engine ECU gets 12V from the ignition
switch, and the Engine-ECU manages fuel injection amount and fuel injec-
tion timing controls that are suited for starting the engine.
Accelerator pedal posi- The engine ECU uses the voltage output from these sensors that fluctu-
tion sensors (main and ates between 0.5 and 5 volts depending on the position of the accelerator
sub) pedal. The Engine-ECU controls fuel injection amount in accordance with
the accelerator pedal position.
Rail pressure sensor Converts the fuel pressure in the common rail into a voltage. The Engine-
ECU uses the voltage to regulate the fuel pressure in the common rail.
Engine coolant tempera- A thermistor that changes its value of resistance based on temperature,
ture sensor affecting the current and the voltage drop in the circuit. The Engine-ECU
can identify the temperature of the engine coolant by the changes in cur-
rent and voltage drops to control the pre-glow time operation as needed,
and the fuel injection amount.

Intake air temperature A thermistor that changes its value of resistance based on temperature,
sensor No. 2 affecting the current and the voltage drop in the circuit. The Engine-ECU
can identify the temperature of the air at the intake manifold (after inter-
cooler) to correct the amount of the exhaust gas recirculation rate.
Fuel temperature sensor A thermistor that changes its value of resistance based on temperature,
affecting the current and the voltage drop in the circuit. The Engine-ECU
can identify the temperature of the fuel at the injection pump to correct the
fuel injection amount that suits to the fuel temperature.
Crank angle sensor Produces a frequency pulsation as the crankshaft is rotated to convert en-
Sensors gine speed and crankshaft position into a voltage signal. Based on this sig-
nal, the Engine-ECU controls the fuel injection amount and fuel injection
timing.
Air flow sensor A wire is heated when a current is applied to it. As air is forced through the
hot wire passage, it will cool the wire to reduce its resistance and change
the value of applied current to the wire. The more air, the more current
output. The engine-ECU uses the current value to identify the air mass,
and calculates the exhaust gas recirculation rate.
Intake air temperature A thermistor that changes its value of resistance based on temperature,
sensor No. 1 affecting the current and the voltage drop in the circuit. The Engine-ECU
can identify the temperature of the air at air flow sensor (before intercooler)
to correct the amount of the exhaust gas recirculation rate.
Throttle position sensor Converts the position of the throttle valve into an output voltage that fluctu-
ates between 0.5 and 5 volts. The Engine-ECU manages fuel, emissions,
timing, shifting, etc. controls based on the throttle valve position.
Camshaft position sen- Produces a frequency pulsation as the camshaft is rotated to convert cam-
sor shaft position into a voltage signal. The Engine-ECU uses this pulsation to
identify the No. 1 cylinder in the top dead center position of the compres-
sion stroke .
EGR valve position sen- A variable resistor that converts the position of the EGR valve into an out-
sor put voltage. The Engine-ECU manages the feedback control for the EGR
valve position.
Manifold absolute pres- Converts the absolute pressure of the inlet manifold into a voltage. The
sure sensor Engine-ECU uses this voltage to control the fuel injection amount.
Vehicle speed sensor Produces a frequency pulsation as output shaft is rotated to convert vehi-
cle speed into a voltage signal. Based on this signal, the Engine-ECU con-
trols the fuel injection amount.

1 - 3 Pub. No. PTAE1228

1. GENERAL


(Continue from previous page)
Name Function
Barometric pressure Converts the barometric pressure into a voltage. The Engine-ECU uses
sensor this voltage to corrects the fuel injection amount and fuel injection timing
that suits to the barometric pressure.
A/C switch Converts the ON/OFF condition of the air conditioner to the Engine-ECU.
A/C load signal The Engine-ECU identifies the drive state of the A/C compressor to control
idle-up engine speed when the compressor is ON..
Power steering fluid The Engine-ECU identifies power steering load to the engine with a ON/
pressure switch OFF switch that causes a voltage change when the steering wheel is rotat-
ed.
Sensors
1st and 2nd rail switch The Engine-ECU identifies with a voltage when the manual transmission is
<M/T> shifted into first gear. The Engine-ECU uses the voltage signal to suppress
the engine speed at start of the vehicle moves.
Back-up lamp switch The Engine-ECU identifies with a voltage when the manual transmission is
<M/T> shifted into Reverse. The Engine-ECU uses the voltage signal to suppress
the engine speed in reverse mortion.

Fuel filter pressure The Engine-ECU identifies a clogged fuel filter when the contact switch
switch located between the fuel filter and the supply pump is forced to make a
change in output voltage .
Injectors An electro mechanical device operated by the Engine-ECU that controls
fuel delivery into the cylinders.
Suction control valve A normally-opened solenoid valve that the Engine-ECU operates in duty
cycle ON/OFF to control the fuel pressure in the common rail.
Engine control relay A relay that it is controlled by the Engine-ECU. When connected, it deliv-
ers power for the operation of the Engine-ECU, sensors and actuators.
Throttle valve control A DC-Motor operated by the Engine-ECU to pulse-control the motion of the
servo throttle valve.
EGR valve (DC motor) A DC-Motor operated by the Engine-ECU to control the motion of the EGR
valve.
Actuators
Glow indicator lamp Illumination lamp to indicate the driver when the engine is ready for
START.
Glow plug relay A relay that it is controlled by the Engine-ECU. When connected, it deliv-
ers power for the operation of the glow plugs.
Condenser fan relay A relay that it is controlled by the Engine-ECU. When connected, it deliv-
<Vehicles with A/C> ers power for the operation of the condenser fan.
A/C relay A relay that it is controlled by the Engine-ECU. When connected, it deliv-
ers power for the operation the A/C compressor.
Engine warning lamp Illumination lamp to indicate the driver when a malfunction exists in the
component of the control system.
























Pub. No. PTAE1228 1 - 4

1. GENERAL


4. KNOWLEDGE CHECK
Regarding the following sentences of the components comprising the common rail fuel system, iden-
tify which ones are correct or incorrect, and make the required correction to the wrong portion of the
incorrect sentence.
(1) The accelerator pedal position sensors detect the position of the accelerator pedal and input it
into the Engine-ECU. Based on the voltage output by these sensors, the Engine-ECU controls ex-
haust gas recirculation amount in accordance with the accelerator pedal position.
(2) The rail pressure sensor detects the fuel pressure in the common rail and input it into the Engine-
ECU. The Engine-ECU uses the voltage that is output by this sensor to regulate the fuel pressure in
the common rail.
(3) The engine coolant temperature sensor uses a thermistor to detect the intake air temperature.
The Engine-ECU determines the warm-up condition of the engine based on the signals output by this
sensor, and controls the pre-glow time and fuel injection amount.
(4) The fuel temperature sensor uses a thermistor to detect the fuel temperature. Based on the volt-
age that is output by this sensor, the Engine-ECU corrects the fuel injection amount to suit the fuel
temperature.
(5) The crank angle sensor detects the engine coolant temperature and camshaft position. Based on
this signal, the Engine-ECU controls the fuel injection amount and fuel injection timing.

(6) The air flow sensor measures the current air mass. The Engine-ECU calculates the exhaust gas
recirculation rate based on this output signal.

(7) Throttle position sensor detects the position of the accelerator pedal and converts it into the out-
put voltage. Based on the voltage output by this sensor, the Engine-ECU manages feedback control
for the accelerator pedal position.

(8) The manifold absolute pressure sensor detects the absolute pressure in the inlet manifold. The
Engine-ECU uses the voltage that is output by this sensor to control the fuel injection amount.

(9) The injectors inject fuel in accordance with the actuation signals provided by the ETACS-ECU.
(10) The suction control valve adjusts the fuel flow into the common rail in accordance with the sig-
nals provided by the Engine-ECU. This allows controlling the fuel pressure in the common rail.




































1 - 5 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


1. LOCATION OF COMPONENTS
The location of sensors, actuators and ECU of the 4D56 common rail system employed on L200 are
shown below.
Name Symbol Name Symbol
Engine warning lamp
Accelerator pedal position sensor S R
(check engine lamp)
A/C compressor relay N 1st and 2nd rail switch <M/T> O
A/C condenser fan relay N Fuel filter pressure switch F
A/C switch U Fuel temperature sensor K
Air flow sensor (incorporating intake air tem-
perature sensor No. 1) A Glow plug lamp R
Back-up lamp switch <M/T> P Glow plug relay M
Camshaft position sensor C Injector B
Crank angle sensor J Intake air temperature sensor No. 2 E
Diagnosis connector T Manifold absolute pressure sensor E
EGR valve (DC motor)
(incorporating EGR valve position sensor) D Power steering fluid pressure switch G
Electronic-controlled throttle valve
(incorporating throttle position sensor) H Rail pressure sensor C
Engine-ECU V Stater relay N
Engine control relay N Suction control valve I
Engine coolant temperature sensor L Vehicle speed sensor <A/T> Q




















































Fig. 2-1

2 - 1 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


2. ENGINE-ECU
The Engine-ECU is an electronic device that relies on input sensors to provide optimal control of the
output actuators required for the constantly changing driving conditions.
Internally, the Engine-ECU consists of a 32-bit microprocessor, a random access memory (RAM), a
read only memory (ROM), and the input-output (I/O) interfaces.
A rewritable flash-memory ROM is incorporated to enable changes or corrections through the use of
a special tool. In addition, an Electrically Erasable Programmable Read Only Memory (EEPROM) is
used so that the learned correction data is not erased even if the battery is disconnected.





















Fig. 2-2


<Injector Drive Circuit>
In order to enhance the prompt response of the injectors, the injector drive signal incorporated in the
Engine-ECU contains a DC/DC converter capable of producing a drive signal of up to 85 volts.



















Fig. 2-3



























Pub. No. PTAE1228 2 - 2

2. SYSTEM COMPONENTS


<ECU Connector Input / Output Pin Arrangement>
<Up to 2010M/Y>










Fig. 2-4

1 No. 1, 4 injector battery 51 EGR position sensor 92 Ignition switch - IG
2 No. 2, 3 injector battery 52 Manifold absolute pressure 96 Power steering switch
sensor
3 No. 3 injector 53 Engine coolant temperature 99 Battery
sensor
4 No. 3 injector 54 Fuel temperature sensor 100 Battery
5 No. 2 injector 55 Rail pressure sensor backup 101 Battery (backup with monitor)
6 No. 2 injector 56 Rail pressure sensor 102 Fuel filter pressure switch
11 Engine check lamp 57 Camshaft position sensor 103 Ignition switch - ST
13 A/C load signal 58 Crank angle sensor 104 1st and 2nd rail switch <M/T>
15 A/C switch 59 Camshaft position sensor pow- 105 Back-up lamp switch <M/T>
er supply
17 Suction control valve (positive) 60 Crank angle sensor power sup- 109 Engine control relay
ply
19 EGR motor (positive) 61 Ground 111 Throttle valve control servo (-)
20 EGR motor (negative) 65 Intake air temperature sensor 112 Accelerator pedal position sen-
No. 2 sor (sub) power supply
22 Ground 70 Intake air temperature sensor 113 Accelerator pedal position
No. 1 ground sensor (sub)
23 No. 1 injector 71 Air flow sensor ground 114 Accelerator pedal position sen-
sor (sub) ground
24 No. 1 injector 72 EGR position sensor ground 117 CAN interface (high)
25 No. 4 injector 73 Manifold absolute pressure 119 Vehicle speed sensor
sensor ground
26 No. 4 injector 74 Engine coolant temperature 120 Accelerator pedal position sen-
sensor ground sor (main) power supply
28 Glow lamp 75 Sensor ground 121 Accelerator pedal position
sensor (main)
29 Glow plug relay 76 Rail pressure sensor ground 122 Accelerator pedal position sen-
sor (main) ground
37 Suction control valve (negative) 78 Camshaft position sensor 124 Throttle position sensor
ground
39 Condenser fan relay <Vehicles 79 Crank angle sensor ground 125 CAN interface (low)
with A/C>
40 A/C relay 80 Sensor source 128 Ground
49 Intake air temperature sensor 81 Rail pressure sensor power 130 Throttle valve control servo (+)
No. 1 supply
50 Air flow sensor 91 Tachometer












2 - 3 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


3. SENSOR
(1) Accelerator Pedal Position Sensor
The accelerator pedal position sensor is mounted on the
accelerator pedal arm, and it outputs a voltage value to
the Engine-ECU that corresponds to the amount of trav-
el of the accelerator pedal. The Engine-ECU uses the
output voltage of the accelerator pedal position sensor
to calculate the fuel injection amount. This accelerator
pedal position sensor uses a non-contact Hall element
to enhance its reliability.







Fig. 2-5


The accelerator pedal position sensor consists of a per-
manent magnet fixed to the pedal shaft and a Hall ele-
ment that outputs an electrical voltage that relates to the
amount of travel of the accelerator pedal.

The stator is fixed to the sensor cover and effectively
guides the magnetic flux from the moving permanent
magnet into the Hall element.


Fig. 2-6


The magnetic flux density that passes into the Hall ele-
ment when the accelerator pedal is not depressed
(closed throttle) is kept to a minimum, and the output
electrical voltage is low.
The magnetic flux density that passes into the Hall ele-
ment when the accelerator pedal is fully depressed
(wide open throttle) produces the maximum electrical
voltage output.










Fig. 2-7


There are two accelerator pedal position sensors in the
same package. One produces the main output voltage
(1v-4.65v), and the other, the sub, produces a second-
ary voltage output (0.5v-2.325v). This improves the ac-
curacy of the system operation. In addition, when a mal-
function is detected, the dual-sensor system reinforces
the failsafe function in order to ensure uninterrupted en-
gine operation.


Fig. 2-8

Pub. No. PTAE1228 2 - 4

2. SYSTEM COMPONENTS


(2) Rail Pressure Sensor
The rail pressure sensor is mounted on the common rail
to convert the fuel pressure in the common rail into a
voltage output. The Engine ECU uses the voltage out-
put to control the operation of the suction control valve in
the injection pump.







Fig. 2-9


The diagram describes the characteristics of this sen-
sor. The voltage output from this sensor fluctuates be-
tween 0.5V and about 4.2V depending on the pressure of
the fuel in the common rail.














Fig. 2-10



(3) Engine Coolant Temperature Sensor
The engine coolant temperature sensor is mounted on
the water outlet fitting to convert the temperature of the
engine coolant temperature into a value of resistance.
The Engine ECU uses the voltage drop as a result of
the changes in resistance to control the pre-glow time
and fuel injection amount in accordance with this input
voltage.



Fig. 2-11


The diagram describes the characteristics of this sen-
sor. When the engine coolant temperature is low, the
sensor resistance is high producing a high voltage drop.
When the temperature of the coolant is high, the re-
sistance of the sensor is low producing a low voltage










Fig. 2-12







2 - 5 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


(4) Intake Air Temperature Sensor No. 2
The intake air temperature sensor No. 2 is mounted on
the intake manifold. It is a thermistor that changes its
value of resistance based on temperature, affecting the
current and the voltage drop in the circuit. The Engine-
ECU can identify the temperature of the air at the intake
manifold (after intercooler) by the voltage drop output
signal to correct the amount of the exhaust gas recircu-
lation rate and the fuel injection amount in accordance
with this input voltage.
Fig. 2-13


The diagram describes the characteristics of this sen-
sor. When the intake air temperature is low, the sensor
resistance is high producing a high voltage drop. When
the temperature of the coolant is high, the resistance of
the sensor is low producing a low voltage drop.







Fig. 2-14



(5) Manifold Absolute Pressure Sensor
The Manifold Absolute Pressure Sensor is mounted on
the cowl top panel and connected to the intake manifold
by means of a vacuum hose, to convert the absolute pres-
sure of the inlet manifold into a voltage value. The Engine-
ECU uses this voltage to correct the fuel injection amount
in accordance with the input voltage.





Fig. 2-15


The diagram describes the characteristics of this sen-
sor. When the intake manifold is at low pressure, the
output voltage is low. When the pressure in the mani-
fold increases as a result of turbo boost acceleration,
the output voltage also increases in direct relation to the
pressure in the manifold.






Fig. 2-16














Pub. No. PTAE1228 2 - 6

2. SYSTEM COMPONENTS


(6) Crank Angle Sensor
The crank angle sensor, which is mounted on the oil
pump case, induces a frequency pulsation as the crank-
shaft is rotated to convert engine speed and crankshaft
position into a voltage signal.
Based on the voltage signal , the Engine-ECU can iden-
tify the cylinders and calculates the engine speed. The
Engine-ECU can also control the fuel injection amount
and fuel injection timing.
Fig. 2-17


The crankshaft sprocket is fitted on the crankshaft. The
rotation of the crankshaft sprocket is identical to the ro-
tation of crankshaft.
When tooth of the crankshaft sprocket is positioned on
front of the magnetic resistance element, the magnetic
flux produced from the magnet passes through the mag-
netic resistance element, increasing the resistance of
the magnetic resistance element.
When the tooth of the crankshaft moves away from the
magnetic resistance element, the magnetic flux pro-
duced from the magnet doesn’t pass through the mag-
netic resistance element, and the resistance of the mag-
netic resistance element decreases.







Fig. 2-18



(7) Camshaft Position Sensor
The camshaft position sensor, which is mounted on the
cylinder head, induces a frequency pulsation as the cam-
shaft is rotated to convert camshaft position into a voltage
signal. The Engine-ECU uses the induced signal voltage
input to identify the cylinders by comparing the pulse
signals output from this sensor and the crank angle sen-
sor. Then the Engine-ECU controls the fuel injection
amount and fuel injection timing. The construction and
operation of the camshaft position sensor is basically
Fig. 2-19 the same as that of the crank angle sensor.






No.1 TDC No.3 TDC No.4 TDC No.2 TDC












Fig. 2-20
2 - 7 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


(8) Air Flow Sensor
The air flow sensor is mounted on the air cleaner hous-
ing to convert the amount of intake air into an output
voltage signal into the Engine-ECU. In addition, the air
flow sensor has a built-in intake air temperature sensor
No. 1 which is described below.

The Engine-ECU uses this input voltage to calculate the
excess air ratio, in order to calculate the amount of EGR
to be introduced.
Fig. 2-21


A thermo-sensing heat-sensing resistor is used to con-
vert the intake air mass flow rate into a voltage output.
The Engine-ECU applies and controls a current to the
heat-sensing resistor, which increases resistance as it
gets hot.








Fig. 2-22

The diagram describes the characteristics of this sen-
sor. When air flows through the sensor, the heat-
sensing resistor releases the heat, reduces the re-
sistance, and increases the output voltage. The more
intake air amount, the more output voltage, and vice
versa.




Fig. 2-23



(9) Intake Air Temperature Sensor No. 1
The intake Air Temperature Sensor No. 1 is mounted in-
side the air flow sensor housing. It is a thermistor that
changes its value of resistance based on temperature, af-
fecting the current and the voltage drop in the circuit. The
Engine-ECU can identify the temperature of the air before
it enters the intercooler to correct the amount of the ex-
haust gas recirculation rate.



Fig. 2-24

The diagram describes the characteristics of this sen-
sor. When the intake air temperature is low, the sensor
resistance is high producing a high voltage drop. When
the temperature of the coolant is high, the resistance of
the sensor is low producing a low voltage drop.






Fig. 2-25
Pub. No. PTAE1228 2 - 8

2. SYSTEM COMPONENTS


(10) Throttle Position Sensor
The throttle position sensor is located in the throttle
body, and converts the rotational angle of the throttle
shaft into an output a voltage signal, which corresponds
to the rotational angle of the throttle valve.
The Engine-ECU operates the throttle actuator control
motor based on the feedback signals of the throttle posi-
tion sensor.


Fig. 2-26


The throttle position sensor uses a non-contact Hall ele-
ment to enhance its reliability. It consists of a perma-
nent magnet fixed to the throttle shaft, a Hall element
that outputs electrical voltage in accordance with the
magnetic flux density, and a stator that effectively
guides the magnetic flux from the permanent magnet
into the Hall element.






Fig. 2-27


The magnetic flux density that passes into the Hall ele-
ment when the throttle valve is fully closed is at its´ mini-
mum, resulting in minimal electrical voltage output. The
magnetic flux density that passes into the Hall element
when the throttle valve is fully open is at its´ maximum,
resulting in maximum electrical voltage output. There-
fore a variable voltage output is produced as the throttle
valve travels between minimum and maximum.











Fig. 2-28


The diagram describes the characteristics of this sen-
sor. When the throttle valve is fully closed the electrical
voltage output is about 0.4V. When the throttle valve is
fully open is the electrical voltage output is about 4.5V.








Fig. 2-29






2 - 9 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


(11) Fuel Temperature Sensor
The fuel temperature sensor is mounted on the supply
pump and converts the temperature of the fuel to an
output voltage to the Engine-ECU. A thermistor changes
its value of resistance based on temperature, affecting the
current and the voltage drop in the circuit. The Engine-
ECU can identify the temperature of the fuel at the injection
pump to correct the fuel injection amount that suits to the
fuel temperature.


Fig. 2-30


The diagram describes the characteristics of this sen-
sor. When the fuel temperature is low, the sensor re-
sistance is high producing a high voltage drop. When
the temperature of the fuel is high, the resistance of the
sensor is low, producing a low voltage drop.







Fig. 2-31



(12) EGR Valve Position Sensor
The EGR valve position sensor is mounted on the EGR
valve to convert the position of the EGR valve into an
output voltage that it is input into the engine-ECU. The
Engine-ECU operates the motor of the EGR valve based
on the feedback control of he EGR valve position.





Fig. 2-32


The diagram describes the characteristics of this sen-
sor. When the EGR valve is closed the output voltage of
the sensor is low. The output voltage of the sensor in-
creases as the EGR valve is fully opened.








Fig. 2-33
















Pub. No. PTAE1228 2 - 10

2. SYSTEM COMPONENTS


(13) Fuel Filter Pressure Switch
The fuel filter pressure switch is installed to the fuel fil-
ter. Using the contact switch, the fuel filter pressure
switch detects the fuel pressure difference between the
fuel filter and the supply pump.
The Engine-ECU identifies a clogged fuel filter when the
contact switch located between the fuel filter and the sup-
ply pump is forced to make a change in output voltage.



Fig. 2-34
























Fig. 2-35
















































2 - 11 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


4. ACTUATOR

QR Code (for ID Code (for (1) Injector
factory use) service use) The injector is a compact and power-saving electro me-
chanical device operated by the Engine-ECU to control
fuel injection timing and injection amount into the cylin-
ders.
The injector consists of a nozzle, command piston, com-
mand chamber, and solenoid valve to control the out-
flow orifice The command piston moves up and down
based on differences of the fuel pressure. The nozzle,
which is integrated with the command piston, moves in
the same manner to open and close the fuel injection
orifice of the injector.
An ID code (consisting of 30 alphanumeric characters)
is stamped on the head of each injector, representing
the injection characteristics of the individual injector.
The Engine-ECU uses this information to properly oper-
ate a mechanical device with an electronic control sys-
tem to ensure a highly accurate fuel injection amount &
timing. When a new injector is placed on an engine, the
ID code must be registered into the Engine-ECU by
means of he MUT-III.
In addition, pilot injection control, which splits the injec-
tion of fuel into two stages, has been adopted.



Fig. 2-36


<No Injection>
When the solenoid valve is OFF, the two-way valve
keeps the outflow orifice of the command chamber
closed. Thus, the high fuel pressure in the command
chamber, together with the command piston, pushes the
nozzle downward. Consequently, the fuel injection ori-
fice (Nozzle) remains closed and does not inject fuel.
<Injection>
When the solenoid valve is ON, the two-way valve
opens, causing the fuel in the command chamber to
flow out from the outflow orifice and reducing the fuel
pressure in the command chamber. As a result, the noz-
zle moves upward, together with the command piston.
Consequently, the fuel injection orifice opens and high-
pressure fuel is injected. When the solenoid valve turns
OFF, the two-way valve closes, instantly pushing the
nozzle downward, and closing the fuel injection orifice.
These ON/OFF operations are performed within an ex-

Fig. 2-37 tremely short amount of time. Therefore, as the solenoid
valve turns ON/OFF twice, it accomplishes one instance
of injection in two stages: pilot injection and main injec-
tion.








Pub. No. PTAE1228 2 - 12

2. SYSTEM COMPONENTS


(2) Throttle Valve Control Servo
The throttle actuator control motor is a DC-Motor operat-
ed by the Engine-ECU to control the motion of the throttle
valve through Pulse Wide Modulation electrical current to
the motor coil. It is installed into the throttle body and
opens or closes the throttle valve via reduction gears.
The Engine-ECU switches the direction of the electrical
current (i.e., polarity), depending on whether it wants to
operate the motor in the opening or closing direction.
The DC motor contains small brushes that offer excel-
Fig. 2-38 lent response and power consumption performance.
This enables the motor to output a rotational power that
is proportionate to the electrical current carrying capaci-
ty imprinted on the coil.



(3) Suction Control Valve
The suction control valve, which is mounted on the sup-
ply pump, is a linear/normally-opened solenoid valve
that the Engine-ECU operates in ON/OFF duty cycle to
control the fuel pressure in the common rail.
The suction control valve controls the amount of fuel
that flows from the feed pump to the high-pressure
chamber, based on duty cycle actuation signals from the
Engine-ECU.
Fig. 2-39
When the ON duty cycle ratio is lower, the valve open-
ing increases. Then the amount of the fuel flowing into
the common rail increases as well as the fuel pressure
in the common rail.
When the ON duty cycle ratio is higher, the valve open-
ing decreases. Then the amount of the fuel flowing into
the common rail decreases as well as the fuel pressure
in the common rail.


(4) EGR Valve (DC Motor)
The EGR valve is located in the middle of the bypass
passage that re-circulates the exhaust gas from the ex-
haust manifold into the intake manifold. It is a type of
DC motor operated by the Engine-ECU that controls the
opening and closing of the valve in accordance with the
changes in the direction of the electrical current.




Fig. 2-40

















2 - 13 Pub. No. PTAE1228

2. SYSTEM COMPONENTS


5. KNOWLEDGE CHECK
Regarding the following sentences of the components comprising a common rail fuel system, identify
which ones are correct or incorrect, and make the required correction to the wrong portion of the in-
correct sentence.

(1) The Engine-ECU consists of a 32-bit microprocessor, random access memory (RAM), read only
memory (ROM), electrically erasable programmable read only memory (EEPROM) and input/output
interfaces.

(2) The accelerator pedal position sensor uses a potentiometer (sliding type variable resistance) to
enhance its reliability.

(3) The accelerator pedal position sensor outputs through two systems (main and sub). This im-
proves the accuracy of the system to detect malfunctions and reinforces the failsafe function in order
to ensure reliability.

(4) The Engine-ECU activates the EGR valve to control the fuel pressure based on the rail pressure
sensor output voltage.

(5) The intake air temperature sensor No.2 outputs the voltage signal into the Engine-ECU, which is
corresponding with the boost air temperature.
(6) The Engine-ECU corrects the fuel injection timing in accordance with the manifold absolute pres-
sure sensor output voltage.

(7) The crank angle sensor, which is mounted on the oil pump case, induces the signal voltage by
using this sensor and crankshaft sprocket and inputs it into the Engine-ECU.

(8) Based on the camshaft position sensor output voltage, the Engine-ECU identifies the cylinders by
comparing the pulse signals output by this sensor and the engine coolant temperature sensor.

(9) The Engine-ECU uses the air flow sensor output voltage to calculate the excess air ratio, in order
to calculate the amount of EGR to be introduced.

(10) The air flow sensor is a Karman’s vortex type that utilizes the dependency of heat transfer on
flow velocity to convert the mass flow rate of the intake air into electrical current.
(11) The throttle position sensor that is located in the throttle body, and uses a non-contact Hall ele-
ment to enhance its reliability.

(12) The fuel temperature sensor, which is mounted on the common rail, detects the temperature of
the fuel through the changes in the resister of it’s the thermistor.

(13) The EGR valve position sensor, which is mounted on the EGR valve, converts the position of the
EGR valve into the electrical signals and inputs it into the engine-ECU.

(14) The fuel filter pressure switch is installed to the common rail. Using the contact switch, the fuel
filter pressure switch detects the fuel pressure difference between the fuel filter and the supply pump.

(15) An ID code (consisting of 30 alphanumeric characters) is stamped on the head of each injector,
representing the injection characteristics of the individual injector.

(16) The throttle valve control servo uses an AC motor that contains small brushes to offer excellent
response and power consumption performance.

(17) The suction control valve, which is a linear solenoid valve that operates under the duty-cycle
rate, is mounted on the supply pump.
(18) The EGR valve is located in the middle of the bypass passage that re-circulates the intake air
from the intake manifold into the exhaust manifold.



Pub. No. PTAE1228 2 - 14

3. SYSTEM OPERATIONS


1. FUEL INJECTION AMOUNT CONTROL
Based on the output signals from various sensors, the Engine-ECU calculates the optimal fuel injec-
tion amount that suits the operating conditions. It then delivers the fuel injection amount by actuating
the injectors´ solenoid valves for each cylinder.


(1) System Configuration Diagram
The Engine-ECU compares the basic fuel injection amount against the maximum fuel injection
amount for the operational condition. It then uses the lower injection amount to calculate the intended
injection amount, which is achieved by controlling the actuation time of the injectors´ solenoid valves.
The longer the solenoid valves actuation time, the greater the injection amount. Conversely, the
shorter the actuation time of the solenoid valves, the lesser will be the injection amount.




























Fig. 3-1
Basic fuel injection amount:
It is calculated based on the signals provided by the accelerator pedal position sensor and the crank
angle sensor.
Maximum fuel injection amount:
It is calculated by applying corrections to the basic fuel injection amount based on various sensors .



(2) Drive Train System Protection Control
This control protects the drive train from extreme loads at start up by controlling the engine speed
under the predetermined speed of 3,000 r/min.
The Engine-ECU controls the fuel injection amount in the following the conditions.
1. When manual transmission shift is in first or reverse
2. When vehicle speed is under 5 km/h.



(3) Learning Pre-Injection Amount
The Engine-ECU determines the variances in the fuel injection amount by monitoring the engine
speed. Based on the changes in engine speed, the Engine-ECU regulates the actual injection
amount for each cylinder by correcting the fuel injection amount command values. The Engine-ECU
stores the correction values in its memory in the form of learning values, and keeps the learned val-
ues stored in its memory until it is updated with subsequent learning values.
The system learns the initial injection amount with a higher injection pressure than normal. It is nor-
mal for the sound of the engine to change while the system is learning the initial injection amount.
The Engine-ECU can perform an injection amount learning automatically, or it can be forced by a
shop technician through the use of the MUT-III.





3 - 1 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


2. FUEL INJECTION TIMING CONTROL
Based on the output signals provided by various sensors, the Engine-ECU calculates the optimal fuel
injection timing that suits the operating conditions. It then controls the fuel injection timing by actuat-
ing the injectors. In addition, the Engine-ECU performs a pilot injection, which injects fuel preceding
the main injection, for the purpose of reducing the generation of combustion sound and NOx emis-
sions.



(1) System Configuration Diagram
Based on the output signals from various sensors, the Engine-ECU calculates the fuel injection tim-
ing by applying corrections to the predetermined basic target fuel injection timing. Thus, it controls
the injection timing by controlling the actuation timing of the injectors.



























Fig. 3-2


(2) Basic Target Fuel Injection Timing
It is calculated based on the crank angle sensor signal and the fuel injection amount.
The system advances the actuation timing of the injectors to advance the injection timing, and retards
the actuation timing of the injectors to retard the injection timing.
However, the ignition is normally retarded only during the main injection, thus increasing the amount
of fuel that it is injected from the start of injection until the fuel is ignited. The result of this is that the
combustion of the fuel occurs suddenly, and at a high temperature & pressure. This increases the
combustion sound and the amount of NOx that is emitted.

Main injection
Pilot injection


Large 1st stage combustion
(cause of Nox and Noise )





Heat generation rate Heat generation rate


TDC TDC
without pilot injection with pilot injection
Fig. 3-3
With the combination of pilot injection and main injection, the pilot injection injects a small amount of
fuel preceding the main injection to make the combustion constant, thus reducing the combustion
sound and the amount of NOx that is emitted.
Pub. No. PTAE1228 3 - 2

3. SYSTEM OPERATIONS


<For Your Reference>
-Multiple stage injection control-
The common rail fuel injection system has the flexibility to inject fuel before and after the main injec-
tion to suit the driving conditions. The system can deliver the injection timing more freely in compari-
son to the diesel fuel system with the mechanical type injection pump, because with the common rail,
the Engine-ECU decides the fuel injection timing when it activates the injector drive signal.

The injection that takes place before the main injection is called pre-injection, which is provided pri-
marily for reducing combustion noise and NOx. And the injection that takes place after the main injec-
tion is called after-injection, which is provided primarily for activating the catalyst.
These fuel injection method is called the multi stage injection control, and the fuel injection that takes
place at the each stage is as follows.

Pilot injection: Fuel is injected way in advance than the main injection to make the pre-mixture com-
bustion which reduces the emission of black smoke, Particulate Matter (PM) and combustion noise.
Pre-injection: Fuel is injected at the approx. 1 msec. ahead of the main injection to create a kind of
trigger flame. This contributes to reduce the ignition delay and to suppress the rapid combustion
pressure increase in the cylinder during the main combustion period. This reduces the emission of
the combustion noise and Nox.
Post injection: Fuel is injected following the main injection so that the combustion of the remaining
un-burn mixture is accelerated and the emission of PM can be reduced.
The timing of the post injection has to take place precisely, otherwise the emission of Nox increases.
After injection: Fuel is injected this late after the main injection to develop an increase of the ex-
haust gas temperature that enhances the activation of the catalyst.






Pre-injection
Fuel injection quantity Pilot injection Main injection Post injection After injection












Time


Fig. 3-4



























3 - 3 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


3. FUEL PRESSURE CONTROL
Based on the signals provided by various sensors, the Engine-ECU calculates the optimal fuel injec-
tion pressure that suits the operating conditions. It then actuates the suction control valve to control
the fuel injection pressure.


<System Configuration Diagram>
Based on the signal input by the crank angle sensor and the fuel injection amount, the Engine-ECU
calculates the fuel injection pressure. It then actuates the suction control valve to control the fuel in-
jection pressure.
In order to appropriately control the fuel injection pressure, the Engine-ECU gets feedback from the
output voltage provided by the rail pressure sensor located in the common rail.
Because the common rail system can maintain a high fuel injection pressure regardless of the engine
speed, it can reduce the amount of particulate matter (PM) and the NOx that are emitted at low en-
gine speeds.


























Fig. 3-5


Toxics <For Your Reference>
Sulphur & metal Particulate Matter (PM) is a term used that includes all
oxides particles in a solid or a liquid state. The size of the parti-
cles differ from 0.05 to 10 micro-meter while a human’s
Sulphur
hair has approximately 60 micro-meter in diameter. The
Sulphate (SO4) typical composition of a particle is shown in figure 3-6.

Carbon The build up of soot particles in a diesel engine depends
on the individual process of diesel combustion, and
Fig. 3-6 takes into consideration air intake, injection and flame
propagation. The combustion quality depends on how
well the fuel is mixed with the air. If the mixture in some
areas of the combustion chamber becomes too rich, the
combustion will then be incomplete and soot particles
will be formed.















Pub. No. PTAE1228 3 - 4

3. SYSTEM OPERATIONS


4. IDLE SPEED CONTROL

<System Configuration Diagram>
The Engine-ECU compares the target idle speed and the actual idle speed. If there is a difference
between the two, the Engine-ECU matches the actual speed to the target idle speed by controlling
the fuel injection amount. In addition, the Engine-ECU monitors the engine speed fluctuations at idle
in order to correct the fuel injection amount of the cylinders. Thus, it reduces the variances in the fuel
injection amount between the cylinders (caused by the injectors) to reduce engine vibrations at idle.



























Fig. 3-7


















































3 - 5 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


5. THROTTLE VALVE OPENING CONTROL
For the throttle body assembly control, the driving condition is detected by means of input signals
from various sensors, and the Engine-ECU then controls the throttle valve control servo in accord-
ance with the driving condition to open and close the throttle valve.


<System Configuration Diagram>





























Fig. 3-8

<Throttle Valve Operation>
When engine is running
The throttle valve control servo is normally off, so that the throttle valve is open.

When engine is stopped
When the ignition switch changes from ON to OFF, the throttle valve control servo turns is activated
for 3 second to close the throttle valve to suffocate the engine. After this, the throttle valve control
servo turns OFF and the throttle valve opens.
With the Diesel engine, engine vibration may happen if the engine is stopped by cutting only the fuel
supply. In order to stop the engine running smoothly when the IG switch is turned OFF, the throttle
valve is fully closed to inhibit air intake for a short period. This operation contributes to improve the
driver’s feeling when the engine stops.

When a problem is developed
The throttle valve closes if diagnostic trouble code No. P0088, P0089, P0191, P0192, P0193, P0219,
P0605, P0606, P0607, P0628, P0629, P1273, or P1275 is generated.
























Pub. No. PTAE1228 3 - 6

3. SYSTEM OPERATIONS


6. POWER SUPPLY CONTROL


<System Configuration Diagram>
When the ignition switch ON signal is input to the Engine ECU from the ignition switch, the Engine-
ECU turns ON the power transistor that provides the ground connection of the engine control relay.
As a result, current flows through the coil in the engine control relay, creating a magnetic field that
causes the relay switch to turn ON and supply power to the sensors and actuators.
When the Engine-ECU detects ignition switch OFF signal, it turns OFF the Engine Control Relay
power transistor after approximately 10 seconds have elapsed.





























Fig. 3-9














































3 - 7 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


7. A/C RELAY CONTROL


<System Configuration Diagram>
For A/C relay control, the driving condition is detected by means of input signals from the various
sensors, and the A/C relay is controlled in accordance with the driving condition. The A/C-ECU ap-
plies system voltage to the Engine-ECU when the air conditioner is running. When an A/C ON signal
is input to the Engine-ECU, the Engine-ECU turns on the power transistor to make the ground con-
nection of the A/C relay. This causes current to flow to the power coil of the A/C relay and magnetize
the switch. The relay switch then turns ON to operate the A/C compressor magnetic clutch.










































Fig. 3-10

































Pub. No. PTAE1228 3 - 8

3. SYSTEM OPERATIONS


8. CONDENSER FAN RELAY CONTROL


<System Configuration Diagram>

























Fig. 3-11


The Engine-ECU controls the condenser fan relay as shown in the charts below.




























Fig. 3-12

























3 - 9 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


9. EMISSION CONTROL (EGR SYSTEM)
Based on the signals received from various sensors, the Engine-ECU actuates the EGR valve to con-
trol the exhaust gas recirculation volume, in order to reduce the amount of NOx (nitric oxide) exhaust.


<System Configuration Diagram>
The amount of NOx (nitric oxide) increases when the combustion chamber gas temperature increas-
es. To reduce the volume of NOx exhaust, the Engine-ECU actuates the EGR valve in accordance
with the operating conditions of the engine. Thus, the Engine-ECU regulates the oxygen concentra-
tion level in the intake air in order to attain an optimal combustion temperature. To enhance accura-
cy, the Engine-ECU utilizes the output voltage signals of the EGR valve position sensor in order to
carry out feedback control on the EGR valve.
When the EGR valve opens, the exhaust gas mixes with the intake air in the intake manifold. This
reduces the ratio of oxygen in the air that is drawn into the combustion chamber. As a result, the
combustion speed decreases, which lowers the combustion temperature and reduces the amount of
NOx exhaust.
Furthermore, an EGR cooler, which significantly lowers the temperature of the exhaust gas that mix-
es with intake air, has been provided in order to increase the recirculation efficiency of the exhaust
gas.










Turbocharger




EGR cooler







Fig. 3-13


<EGR Cooler>
The EGR cooler used is the laminated type, and it is
installed between the exhaust manifold and the ex-
haust gas recirculation valve.
The EGR cooler lowers the temperature of the ex-
haust gas that is being recalculated in order to en-
hance the charging efficiency of exhaust gas recircula-
tion amount.



Fig. 3-14














Pub. No. PTAE1228 3 - 10

3. SYSTEM OPERATIONS


10. GLOW PLUG RELAY/ GLOW INDICATOR LAMP CONTROLS
The Glow system, which consists of the glow plug relay control and the glow indicator lamp control,
warms up the combustion chamber in accordance with the actuation signals from the Engine-ECU,
and advices the driver when it is to crank the engine. This ensures the proper start-ability and stabi-
lizes the running conditions of the engine at low temperatures.
The self-regulating glow system enables the vehicle to start ideally at low temperature by preheating
the glow plug at super speed. When the ignition switch is turned to the ON position, the Engine-ECU
supplies electric currents and controls the glow lamp illumination in accordance with the engine cool-
ant temperature. The control resistance wire built in the glow plug has a higher resistance as the
glow plug temperature becomes higher. Because of this, the currents in the heater wire gradually de-
crease. The glow plug is stabilized at the specified temperature. After the engine start at low temper-
ature, the current going to the glow plug is controlled to perform the stable combustion.
(1) Glow Plug Relay Control
<System Configuration Diagram>



























Fig. 3-15



Engine-ECU















Fig. 3-16 Fig. 3-17


















3 - 11 Pub. No. PTAE1228

3. SYSTEM OPERATIONS


Engine-ECU turns ON the glow plug relay when the following conditions are met.
Before starting (pre-glow control)
◇ Ignition switch is ON.
◇ Engine coolant temperature is 60°C or less.
◇ The maximum length of time during which the glow plug relay remains ON is 10 seconds.
While running a cold engine (after-glow control)
◇ Ignition switch-IG signal is ON.
◇ Engine coolant temperature is 60°C or less.
◇ Engine speed is 350 r/min or more.
◇ The maximum length of time during which the glow plug relay remains ON is 180 seconds.

<Glow Plug Energization Time Chart>

























Fig. 3-18


<Glow Plug>
The glow plug, which is installed in each cyl-
inder on the cylinder head, consists of the
ceramic element in which a heater wire and
a self-control resistor are integrated.
When the current is applied to the glow plug,
the ceramic element gets warmer and the
Heating element resistance increases. The current flow in the
ceramic element is gradually reduced and
less heat is produced in the glow plug.
Fig. 3-19


(2) Glow Indicator Lamp Control
When the engine coolant temperature is below a predetermined level, the Engine-ECU sends a sig-
nal to the combination meter via CAN (Controller Area Network) to request the illumination of the
glow indicator lamp. This causes the glow indicator lamp to illuminate, in order to inform the driver of
the timing for starting the engine.
















Pub. No. PTAE1228 3 - 12

3. SYSTEM OPERATIONS


11. KNOWLEDGE CHECK
Regarding the following sentences of a common rail fuel system operation, identify which ones are
correct or incorrect, and make the required correction to the wrong portion of the incorrect sentence.

(1) Basic fuel injection amount is calculated based on the signals provided by the air flow sensor and
the crank angle sensor.

(2) Basic target fuel injection timing is calculated based on the crank angle sensor signal and the fuel
injection amount.
(3) Based on the signal input by the crank angle sensor and the fuel injection amount, the target fuel
injection pressure is calculated. And the Engine-ECU actuates the throttle control servo to control the
fuel injection pressure.
(4) The Engine-ECU compares the target idle speed and the actual idle speed. If there is a difference
between the two, the Engine-ECU matches the actual speed to the target idle speed by controlling
the fuel injection amount.
(5) In the throttle valve opening control, when the ignition switch changes from on to off, the throttle
valve control servo turns on for 3 second to open the throttle valve.

(6) When the ignition switch OFF signal is input by the ignition switch, the Engine-ECU turns OFF the
power transistor for controlling the engine control relay after approximately 10 seconds have elapsed.

(7) When an A/C ON signal is input to the Engine-ECU, the Engine-ECU turns on the power transis-
tor. This causes current to flow to the power coil of the A/C relay. The relay switch then turns on to
operate the blower fan motor.

(8) Based on the signals received from various sensors, the Engine-ECU actuates the EGR valve to
control the exhaust gas recirculation volume, in order to reduce the amount of NOx (nitric oxide) ex-
haust.

(9) Glow system, which consists of glow plug relay control and glow indicator lamp control, warms up
the combustion chamber in accordance with the actuation signals from the Engine-ECU. This en-
sures the proper start-ability and stabilizes the running conditions of the engine at high temperatures.








































3 - 13 Pub. No. PTAE1228

4. CONTROLLER AREA NETWORK (CAN)


1. GENERAL
CAN, an abbreviation for Controller Area Network, is an ISO-certified international standard for a seri-
al multiplex communication protocol . A communication circuit employing the CAN protocol connects
*1
all the ECUs in a network, and all sensor data can be shared among all the ECUs, which significantly
reduces the size and complexity of the wiring harness.
CAN offers the following advantages.
◇ Transmission rates are much faster than those in conventional communication protocols (up to 1
*2
Mbps ), allowing much more data exchange.
◇ The system has high resistance to the effects of external noise, and the error detection function
is provided for each composing device. This can achieve excellent reliability as a system.
◇ Each ECU connected via the CAN communicates independently. Therefore even if the system
has a failure, the communication is not interrupted and can be continued even with a failure con-
dition.
◇ : The regulations have been decided in detail, from software matters such as the nec-
*1
essary transmission rate for communication, the system, data format, and communica-
Note tion timing control method to hardware matters such as the harness type and length
and the resistance values.
◇ *2 : bps=bit per second


2. STRUCTURE
























Fig. 4-1


◇ The CAN bus line consists of two lines, CAN_L and CAN_H (CAN Low and CAN High, respec-
tively), as well as two terminal resistors of approximately 120 Ω each located at the ends of the
lines. A twisted-pair cable, highly resistant to noise, is used for the communications line.
◇ The CAN bus line connecting the two terminal resistors is refer as the main bus line, and the
CAN bus line connecting other ECUs are the sub-bus line.
◇ In this vehicle, the terminal resistors are installed in the ETACS-ECU and Engine-ECU to stabi-
lize the communication signals.
◇ In the CAN bus line the following ECUs and terminal resistor are connected.
◆ Engine-ECU
◆ Terminal resistor
◆ A/T-ECU
◆ A/C-ECU
◆ ABS-ECU
◆ RV meter
◆ ETACS-ECU
◆ Immobilizer-ECU



4 - 1 Pub. No. PTAE1228

4. CONTROLLER AREA NETWORK (CAN)


3. SYSTEM OPERATION
























Fig. 4-2
The CAN communication system is described below.
◇ Each ECU communicating with CAN periodically sends several sensors’ information through the
CAN bus as data frame (called periodical sending data).
◇ ECUs requiring data on CAN bus can receive data frames sent from each ECU simultaneously.
◇ The data sent from each ECU conducting CAN communication is transmitted at 0.01 - 1 sec in-
terval depending on necessity of data.
In the figure above, the data frame A is transmitted in "a" intervals, while the data
Note
frames B and C are transmitted at intervals "b" and "c," respectively.

◇ A single ECU transmits multiple data frames.
◇ When data frames conflict with one another (when many ECUs transmit signals simultaneously),
data is prioritized for transmission by mediation, therefore, plural data frames are not sent simul-
taneously.
◇ Data is transmitted not by the conventional voltage-using method, but by voltage potential differ-
ence.
◇ Reliability of each ECU transmitting signals via CAN communication is secured by several error
detection and recovery processes.



<Mediation>
Because each ECU transmits data independently on the CAN bus, there are cases of data collision
when multiple ECUs attempt to transmit data frames simultaneously (i.e., multiple ECUs transmit at
nearly the same moment). Whenever this happens, the processing of the ECUs attempting trans-
mission is performed in the following way.

1. Data frame with high priority is transmitted first according to ID codes memorized in data frames.
2. Transmission of low-priority data (data frames) is suspended by the issuing ECUs until the bus
clears (when no transmission data exists on the CAN bus).
If the suspended state continues for a specific time, new data (data frame content) is
Note
created and sent.
3. ECU containing suspended data frames transmits the data when the bus becomes available.

There is enough capacity on the CAN bus, which never prevents data frames from be-
Note
ing sent.








Pub. No. PTAE1228 4 - 2

4. CONTROLLER AREA NETWORK (CAN)


4. VOLTAGE TRANSFORMATION ON THE CAN BUS




















Fig. 4-3

Data frame transmission through the CAN bus line involves an output signals of voltage transfor-
mation in the distinctive CAN profile as follows. The ECU transmitting through the CAN_H and
CAN_L bus lines sends 2.5 - 3.5 V signals through the CAN_H side and 2.5 - 1.5 V signals through
the CAN_L side. The receiving ECU reads the data from the CAN_H and CAN_L potential difference.
"Recessive" refers to the state where both CAN_H and CAN_L are at the 2.5 V state, and "Dominant"
refers to the state where CAN_H is at the 3.5 V state and CAN_L is at the 1.5 V state (i.e. a 2V differ-
ence).
This communication has some advantages. First even if one of the lines is ground and the voltage of
the line goes to 0V, communication can continue uninterrupted by the unaffected line. Also, the em-
ployment of dual communications lines improves reliability to prevent the presence of noise as com-
pared to the conventional communication method.



5. SELF-DIAGNOSIS
CAN self-diagnosis is performed by each ECU connected to the CAN bus.
Diagnosis codes related to communication are identified by the capital letter U, and are called "U-
codes." A summary of the CAN self-diagnosis system is presented below.
<Time-Out>
Each ECU transmits data frames periodically. If the data frame is not received within the specified
period, the intended receiving ECU transmits a diagnosis code indicating communication time-out for
the ECU that failed to transmit.
<Bus Off>
Related to a communication error that persists even after the transmitting ECU attempts recovery for
a specified number of attempts or that persists for a specified period after recovery. Communication
is stopped and this diagnostic code is issued.
<Failure Data>
When the transmitting ECU detects failure of a sensor directly connected to it, this is the pertinent
data used to inform the ECU.




6. CAN BUS DIAGNOSTICS
The MUT connects directly to the CAN bus when conducting a diagnosis. Use the MUT III to confirm
the normal operation of the CAN bus by conducting the following inspections:
◇ Voltage measurement between the CAN_L and CAN_H and the body earth terminal
◇ Resistance measurement between the CAN_L and CAN_H
◇ Confirmation of communication of all ECUs






4 - 3 Pub. No. PTAE1228

4. CONTROLLER AREA NETWORK (CAN)


7. KNOWLEDGE CHECK
Regarding the following sentences of a controller area network, identify which ones are correct or in-
correct, and make the required correction to the wrong portion of the incorrect sentence.
(1) CAN, an abbreviation for Contact Area Network, is an ISO-certified international standard for a
serial multiplex communication protocol.

(2) A communication circuit employing the CAN protocol connects each ECU, and sensor data can
be shared among, which enables more reduction in number of wiring harness.
(3) The CAN bus line consists of two lines, CAN_L (left) and CAN_R (Right) that are twisted-pair ca-
ble, highly resistant to noise.
(4) When data frames conflict with one another (when plural ECUs are going to transmit signals sim-
ultaneously), data is prioritized for transmission by mediation, therefore, plural data frames are not
sent simultaneously.







































































Pub. No. PTAE1228 4 - 4

5. DIAGNOSIS SYSTEM


The Engine -ECU has been provided with the following
functions for easier system inspection.

1. ENGINE WARNING LAMP (CHECK ENGINE LAMP)
Engine warning lamp is lit when any abnormality takes
place in the item related to electronically controlled fuel
injection system shown in the following table.
If the malfunction indicator lamp has been on and/or is
lit when the engine is in operation, check the diagnosis
output.

Fig. 5-1

(1) Engine Warning Lamp Inspection Items <Vehicles with Immobilizer System>

Code No. Diagnosis item
- Engine-ECU
P0016* Crank angle sensor/camshaft position sensor phase problem
P0072 Intake air temperature sensor No. 2 circuit low input
P0073 Intake air temperature sensor No. 2 circuit high input
P0088* Common rail pressure malfunction
P0089* Suction control valve stuck
P0093* Fuel leak problem
P0102 Air flow sensor circuit low input
P0103 Air flow sensor circuit high input
P0106 Manifold absolute pressure sensor range/performance problem
P0107 Manifold absolute pressure sensor circuit low input
P0108 Manifold absolute pressure sensor circuit high input
P0112 Intake air temperature sensor No. 1 circuit low input
P0113 Intake air temperature sensor No. 1 circuit high input
P0117 Engine coolant temperature sensor circuit low input
P0118 Engine coolant temperature sensor circuit high input
P0122 Throttle position sensor circuit low input
P0123 Throttle position sensor circuit high input
P0182 Fuel temperature sensor circuit low input
P0183 Fuel temperature sensor circuit high input
P0191* Rail pressure sensor range/performance problem
P0192* Rail pressure sensor low input
P0193* Rail pressure sensor high input
P0201* No. 1 Injector circuit malfunction
P0202* No. 2 Injector circuit malfunction
P0203* No. 3 Injector circuit malfunction
P0204* No. 4 Injector circuit malfunction
P0234* Turbocharger over-boost condition
P0301 No. 1 cylinder injector malfunction (No injection)
P0302 No. 2 cylinder injector malfunction (No injection)
P0303 No. 3 cylinder injector malfunction (No injection)
P0304 No. 4 cylinder injector malfunction (No injection)
P0335* Crank angle sensor system
P0336* Crank angle sensor range/performance problem
P0340* Camshaft position sensor system
P0341* Camshaft position sensor range/performance problem
P0403 EGR valve (DC motor) malfunction
P0405 EGR valve position sensor circuit low input
P0406 EGR valve position sensor circuit high input
P0502 Vehicle speed sensor low input
P0513* Immobilizer malfunction
P0551 Power steering fluid pressure switch system
5 - 1 Pub. No. PTAE1228

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
Code No. Diagnosis item
P0603 EEPROM malfunction
P0604 Random access memory (RAM) malfunction
P0605* Read only memory (FLASH ROM) malfunction
P0606* Engine-ECU (main CPU) malfunction
P0607* Engine-ECU (sub CPU) malfunction
P0628* Suction control valve open
P0629* Suction control valve battery short
P0630* Chassis number not programmed
P0638 Throttle valve control servo stuck
P0642* Analog sensor reference voltage No. 1 too low
P0643* Analog sensor reference voltage No. 1 too high
P0652* Analog sensor reference voltage No. 2 too low
P0653* Analog sensor reference voltage No. 2 too high
P1203* Capacitor insufficient charging
P1204* Capacitor excessive charging
P1272* Pressure limiter malfunction
P1273* Supply pump insufficient flow
P1274* Supply pump protection
P1275* Supply pump exchange
P1276 Fuel filter exchange
P1625* Injection quantity compensation valve error
P1626* Injection quantity compensation valve not coding
P2118 Throttle valve control (DC motor) current malfunction
P2122* Accelerator pedal position sensor (main) circuit low input
P2123* Accelerator pedal position sensor (main) circuit high input
P2127* Accelerator pedal position sensor (sub) circuit low input
P2128* Accelerator pedal position sensor (sub) circuit high input
P2138* Accelerator pedal position sensor (main and sub) range/performance problem
P2146* Injector common 1 (cylinder No. 1 and No. 4) circuit open
P2147* Injector common circuit earth short
P2148* Injector common circuit battery short
P2149* Injector common 2 (cylinder No. 2 and No. 3) circuit open
P2228 Barometric pressure sensor circuit low input
P2229 Barometric pressure sensor circuit high input
P2413 EGR system performance


(2) Diagnosis Using Diagnosis 2 Mode
1. Switch the diagnosis mode of the engine control unit to DIAGNOSIS 2 mode using the MUT-III.
2. Carry out a road test.
3. Take a reading of the diagnosis code and repair the problem location
4. Turn the ignition switch to OFF and then back to ON again.
By turning the ignition switch to OFF, the engine-ECU will switch the diagnosis mode from
Note
DIAGNOSIS 2 mode to DIAGNOSIS 1 mode.
5. Erase the diagnosis codes.
















Pub. No. PTAE1228 5 - 2

5. DIAGNOSIS SYSTEM


2. FREEZE-FRAME DATA
When the Engine-ECU detects a problem and stores the resulting diagnosis code, the engine condi-
tion at that time is also memorized as a freeze frame. The MUT-III can then be used to analyze this
data in order to increase the effectiveness of troubleshooting. The freeze-frame data display items
are shown as follows.
Item No. Data Unit
2 Ignition cycle -
4 Accumulated minute min

3. DIAGNOSIS CODE
The diagnosis trouble codes and status of the engine warning lamp items are given in the table be-
low.
Engine warning
Code No. Diagnosis item
lamp
P0016* Crank angle sensor/Camshaft position sensor phase problem ON
P0072 Intake air temperature sensor No. 2 circuit low input ON
P0073 Intake air temperature sensor No. 2 circuit high input ON
P0088* Common rail high pressure malfunction ON
P0089* Suction control valve stuck ON
P0093* Fuel leak problem ON
P0102 Air flow sensor circuit low input ON
P0103 Air flow sensor circuit high input ON
P0106 Manifold absolute pressure sensor range/performance problem ON
P0107 Manifold absolute pressure sensor circuit low input ON
P0108 Manifold absolute pressure sensor circuit high input ON
P0112 Intake air temperature sensor No. 1 circuit low input ON
P0113 Intake air temperature sensor No. 1 circuit high input ON
P0117 Engine coolant temperature sensor circuit low input ON
P0118 Engine coolant temperature sensor circuit high input ON
P0122 Throttle position sensor circuit low input ON
P0123 Throttle position sensor circuit high input ON
P0182 Fuel temperature sensor circuit low input ON
P0183 Fuel temperature sensor circuit high input ON
P0191* Rail pressure sensor range/performance problem ON
P0192* Rail pressure sensor low input ON
P0193* Rail pressure sensor high input ON
P0201* No. 1 Injector circuit malfunction ON
P0202* No. 2 Injector circuit malfunction ON
P0203* No. 3 Injector circuit malfunction ON
P0204* No. 4 Injector circuit malfunction ON
P0219 Engine over-speed condition OFF
P0234* Turbocharger over-boost condition ON
P0301 No. 1 Cylinder injection malfunction (no injection) ON
P0302 No. 2 Cylinder injection malfunction (no injection) ON
P0303 No. 3 Cylinder injection malfunction (no injection) ON
P0304 No. 4 Cylinder injection malfunction (no injection) ON
P0335* Crank angle sensor system ON
P0336* Crank angle sensor range/performance problem ON
P0340* Camshaft position sensor system ON
P0341* Camshaft position sensor range/performance problem ON
P0403 EGR valve (DC motor) malfunction ON
P0405 EGR valve position sensor circuit low input ON
P0406 EGR valve position sensor circuit high input ON
P0502 Vehicle speed sensor low Input ON
P0513* Immobilizer malfunction ON
P0551 Power steering fluid pressure switch system ON
5 - 3 Pub. No. PTAE1228

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
P0603 EEPROM malfunction ON
P0604 Random access memory (RAM) malfunction ON
P0605* Read only memory (FLASH ROM) malfunction ON
P0606* Engine-ECU (main CPU) malfunction ON
P0607* Engine-ECU (sub CPU) malfunction ON
P0628* Suction control valve open ON
P0629* Suction control valve battery short ON
P0630* Chassis number not programmed ON
P0638 Throttle valve control servo stuck ON
P0642* Analog sensor reference voltage No. 1 too low ON
P0643* Analog sensor reference voltage No. 1 too high ON
P0652* Analog sensor reference voltage No. 2 too low ON
P0653* Analog sensor reference voltage No. 2 too high ON
P1203* Capacitor insufficient charging ON
P1204* Capacitor excessive charging ON
P1272* Pressure limiter malfunction ON
P1273* Supply pump insufficient flow ON
P1274* Supply pump protection ON
P1275* Supply pump exchange ON
P1276 Fuel filter exchange ON
P1625* Injection quantity compensation value error ON
P1626* Injection quantity compensation value not coding ON
P2118 Throttle valve control (DC motor) current malfunction ON
P2122* Accelerator pedal position sensor (main) circuit low input ON
P2123* Accelerator pedal position sensor (main) circuit high input ON
P2124 Accelerator pedal position sensor (main) circuit high input intermittent OFF
P2127* Accelerator pedal position sensor (sub) circuit low input ON
P2128* Accelerator pedal position sensor (sub) circuit high input ON
P2138* Accelerator pedal position sensor (main and sub) range/performance problem ON
P2146* Injector common 1 (cylinder No. 1and No. 4) circuit open ON
P2147* Injector common circuit earth short ON
P2148* Injector common circuit battery short ON
P2149* Injector common 2 (cylinder No. 2 and No. 3) circuit open ON
P2228 Barometric pressure sensor circuit low input ON
P2229 Barometric pressure sensor circuit high input ON
P2413 EGR system performance ON
U1073 Bus off OFF
U1101** A/T-ECU time-out OFF
U1102** ASTC-ECU time-out OFF
U1109** ETACS time-out OFF
U1117** Immobilizer-ECU time-out OFF
U1190 The network system diagnosis code output permitted signal can not be re- OFF
ceived

After the Engine-ECU has detected a malfunction, the engine warning lamp illuminates
when the engine is next turned on and the same malfunction is re-detected. However, for
items marked with a "*" in the diagnosis code number column, the engine warning lamp
Note illuminates only on the first detection of the malfunction.
When the fuel runs out, it is possible that the engine warning lamp may illuminate. After
refilling the fuel, the engine warning lamp turns OFF but the diagnosis code Nos. P1272
and P1273 remain stored.


**: When the diagnosis codes relating to the CAN communication error are output, make
Note sure of the vehicle equipment. When the vehicle is not equipped with the system the En-
gine-ECU communicates to, the diagnosis code is always output. This is not abnormal.
Pub. No. PTAE1228 5 - 4

5. DIAGNOSIS SYSTEM


4. DATA LIST FUNCTION
The data list items and their reference value are given in the table below.
No. Items Inspection conditions Normal value
1 Battery voltage IG switch: ON System voltage

2 Engine revolution Engine: Cranking Compare tachometer reading and MUT-III dis- To be matched
play

Engine: Idling When the engine coolant temperature: -20 °C 900 r/min
Transmission: Neu-
tral or P range When the engine coolant temperature: 0 °C 900 r/min
A/C switch: OFF
When the engine coolant temperature: 25 °C 850 r/min

When the engine coolant temperature: 40 °C 800 r/min
When the engine coolant temperature: 80 °C 700 r/min
3 Target Idle speed Engine: Idling When the engine coolant temperature: -20 °C 900 r/min
Transmission: Neu-
tral or P range When the engine coolant temperature: 0 °C 900 r/min
A/C switch: OFF When the engine coolant temperature: 25 °C 850 r/min

When the engine coolant temperature: 40 °C 800 r/min
When the engine coolant temperature: 80 °C 700 r/min
4 Vehicle speed Drive 40 km/h Approx. 40 km/h
sensor
5 Barometric pres- IG switch: ON Altitude 0 m 101 kPa
sure sensor
Altitude 600 m 95 kPa
Altitude 1,200 m 88 kPa
Altitude 1,800 m 81 kPa

6 Manifold absolute IG switch: ON or Altitude: 0 m 101 kPa
pressure sensor Idling
Engine coolant Altitude: 600 m 95 kPa
temp.: 85 - 95°C Altitude: 1,200 m 88 kPa
All lights/
accessories: OFF Altitude: 1,800 m 81 kPa
Transmission: Neu- When engine is suddenly raced. To be varied
tral or P range
7 Engine coolant IG switch: ON or When the engine coolant temperature is -20°C -20°C
temperature sen- Engine running
sor When the engine coolant temperature is 0°C 0°C
When the engine coolant temperature is 20°C 20°C
When the engine coolant temperature is 40°C 40°C
When the engine coolant temperature is 80°C 80°C

8 Intake air tempera- IG switch: ON or When the intake air temperature is -20°C -20°C
ture sensor No. 2 Engine running
When the intake air temperature is 0°C 0°C
When the intake air temperature is 20°C 20°C
When the intake air temperature is 40°C 40°C

When the intake air temperature is 80°C 80°C









5 - 5 Pub. No. PTAE1228

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
No. Items Inspection conditions Normal value
9 Accelerator pedal IG switch: ON Release the accelerator pedal 700 - 1,300 mV
position sensor Depress the accelerator pedal gradually Increases with the
(main) pedal stroke
Depress the accelerator pedal fully 4,000 mV or more
10 Accelerator pedal IG switch: ON Release the accelerator pedal 200 - 800 mV
position sensor Depress the accelerator pedal gradually Increases with the
(sub) pedal stroke
Depress the accelerator pedal fully 2,000 mV or more
11 Accelerator pedal IG switch: ON Release the accelerator pedal 0%
position sensor Depress the accelerator pedal gradually Increases with the
(main) pedal stroke
Depress the accelerator pedal fully 98 % or more
12 Accelerator pedal IG switch: ON Release the accelerator pedal 20 % or below
position sensor Depress the accelerator pedal gradually Increases with the
(sub) pedal stroke
Depress the accelerator pedal fully 98 % or more
15 Vehicle speed Drive 40 km/h Approx. 40 km/h
sensor
16 EGR valve posi- Engine: After warming Idling 50 % or more*
tion sensor up
Transmission: Neutral 3,500 r/min or more 10 % or below
or P range
17 EGR valve target Engine: After warming Idling 50 % or more
position up
Transmission: Neutral 3,500 r/min or more 10 % or below
or P range
21 Fuel temperature IG switch: ON or When the fuel temperature is -20°C -20°C
sensor Engine running When the fuel temperature is 0°C 0°C
When the fuel temperature is 20°C 20°C
When the fuel temperature is 40°C 40°C
When the fuel temperature is 80°C 80°C
25 A/C switch Engine: Idling after A/C switch: OFF OFF
warming up A/C switch: ON (A/C compressor in operation) ON

26 A/C load signal Engine: Idling after Magnet clutch is not in operation ON
<Vehicles with A/C warming up Magnet clutch is in operation OFF
condenser fan> A/C switch: ON
27 A/C relay Engine: Idling after A/C switch: OFF OFF (Magnet clutch
warming up is not in operation)
A/C switch: ON ON (Magnet clutch is
in operation)
28 AT/MT switch IG switch: ON Vehicles with M/T M/T
Vehicles with A/T A/T
29 Condenser fan IG switch: ON A/C switch: OFF OFF
relay Engine coolant temp.: 97°C or lower
A/C switch: ON ON
Vehicle speed: 60 km/h or lower
30 Control relay IG switch: ON ON
33 Engine check IG switch: "OFF" → "ON" "ON" → "OFF" (after
lamp 5 seconds have
elapsed)
35 Glow lamp IG switch: "OFF" → "ON" "OFF" → "ON" (After
Engine coolant temperature: lower than 60 °C several seconds
have elapsed)
Pub. No. PTAE1228 5 - 6

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
No. Items Inspection conditions Normal value
36 Glow plug relay IG switch: "OFF" → Engine coolant temperature: lower than 60 °C ON
"ON" Engine coolant temperature: higher than 60 °C OFF
38 Ignition switch IG switch: ON ON
40 Starter switch IG switch: ON Engine: Except cranking OFF
Engine: Cranking ON
43 Intake air tempera- IG switch: ON Intake air temperature: -20°C -20°C
ture sensor No. 1 Intake air temperature: 0°C 0°C
Intake air temperature: 20°C 20°C
Intake air temperature: 40°C 40°C
Intake air temperature: 80°C 80°C
45 Throttle position -Remove the intake air Fully close the throttle valve with your finger 300 - 700 mV
sensor hose at the throttle
body
-Disconnect the con-
nector of the electronic
-controlled throttle
valve
-With the special tool
test harness
(MB991658) bridge
only the mating termi-
nals of No. 1, No. 2,
and No. 4 of the dis-
connected connectors
-IG switch: ON (engine
stopped)
Fully open the throttle valve with your finger 4,000 mV or
higher
47 Throttle position -Remove the intake air Fully close the throttle valve with your finger 0 - 5 deg
sensor hose at the throttle
body
-Disconnect the con-
nector of the electronic
-controlled throttle
valve
-With the special tool
test harness
(MB991658) bridge
only the mating termi-
nals of No. 1, No. 2,
and No. 4 of the dis-
connected connectors
-IG switch: ON (engine
stopped)
Fully open the throttle valve with your finger 73 deg or higher
56 Engine revolution Engine: Cranking Compare tachometer reading and MUT-III dis- To be matched
play
Engine: Idling When the engine coolant temperature: -20°C 900 r/min
Transmission: Neu- When the engine coolant temperature: 0°C 900 r/min
tral or P range
A/C switch: OFF When the engine coolant temperature: 25°C 850 r/min
When the engine coolant temperature: 40°C 800 r/min
When the engine coolant temperature: 80°C 700 r/min










5 - 7 Pub. No. PTAE1228

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
No. Items Inspection conditions Normal value
63 Rail pressure sen- Engine coolant Idling Fuel pressure tar-
sor temp.: 85 - 95°C get ± 10 MPa
All lights/
accessories: OFF Depress the accelerator pedal gradually Fuel pressure tar-
Transmission: Neu- get ± 15 MPa
tral or P range
64 Rail pressure tar- Engine coolant Idling 20 - 35 MPa
get temp.: 85 - 95°C
All lights/ Depress the accelerator pedal gradually Increases with the
accessories: OFF pedal stroke
Transmission: Neu-
tral or P range
66 Supply pump IG switch: ON -300 to 300 mA
learned value
72 1st and 2nd rail IG switch: ON Shift position: 1st or 2nd ON
shift switch <M/T>
Shift position: other than 1st or 2nd OFF
73 Reverse shift IG switch: ON Shift position: reverse ON
switch <M/T>
Shift position: except reverse OFF
75 Power steering Engine: running Steering wheel: stationary OFF
fluid pressure
switch Steering wheel: turning ON
114 Air flow sensor Engine coolant Idle operation 725 - 935 mg/cyl
temp.: 85 - 95°C
ALL lights/
accessories: OFF
Transmission: Neu-
tral or P range







152 Fuel filter pressure IG switch: ON OFF
switch
Engine: Idling ON
Squeeze the fuel hose with one’s fingers at the inlet side of the
fuel filter



*: The value shows when outside temperature is approximately 20°C. When the EGR valve
position sensor is checked at the outside temperature of 20°C or more, the value would be
Note possibly below the opening degree (normal value). Also, the value would be possibly below
the opening degree (normal value) under the lowered volumetric efficiency due to the intake
air temperature rises.


















Pub. No. PTAE1228 5 - 8

5. DIAGNOSIS SYSTEM


<Engine-ECU Monitor Item>
The Engine-ECU uses the following item data to identify the necessary engine control conditions.
As the engine is operated and wear and tear occurs, the values of these monitor items vary greatly
depending on marginal difference of measurement conditions, difference of the environment, aged
deterioration of vehicles and so on, and it is difficult to show the precise specification values. There-
fore, check conditions, display range and movement of values are described in general terms.

No. Item Meaning of the item Inspection condition Normal value
13 Accelerator pedal position Learning value of not de- IG switch: ON 700 - 1,300mV
sensor (main) learned pressed accelerator pedal
closed position state is shown
46 Throttle position sensor Learning value of fully closed IG switch: ON 9 deg or less
learned closed position throttle valve state is shown
57 Fuel quantity final Indicates the final injection Engine: After warm-up, idling 3 - 10 mm3/st
quantity All lights/accessories: OFF
Transmission: Neutral or P range
58 Fuel quantity pilot Indicates the pilot injection Engine: After warm-up, idling 0.5 - 3 mm3/st
quantity All lights/accessories: OFF
Transmission: Neutral or P range
59 Fuel quantity smoke limit Indicates the limit of injection Engine: After warm-up, 2,000r/ 35 mm3/st or
quantity determined by the min more
charging pressure
60 Fuel quantity start Indicates the pilot injection IG switch: At engine coolant 40 - 50 mm3/st
quantity determined by water ON temp. is 0°C
temperature At engine coolant 30 - 40 mm3/st
temp. is 70°C
61 Fuel injection interval pilot Interval between end of pilot Engine: After warm-up 200 - 2,000 us
injection and start of main
injection
62 Fuel injection timing main Main injection timing Engine: After warm-up, idling -3 to 4°CA
65 Supply pump learned sta- Although the fuel discharge IG switch: ON 2*
tus quantity is decided depending on
the drive current of the suction
control vale of the supply pump,
learning is executed in idle state
because there is a machine dif-
ference. The learned status is
indicated.
78 Small injection quantity at Indicates the final learned value IG switch: ON -0.41 to 0.36
pressure 1 - No. 1 cylinder of the small injection quantity of ms
No. 1 cylinder at 25 MPa
79 Small injection quantity at Indicates the final learned value IG switch: ON -0.41 to 0.36
pressure 1 - No. 2 cylinder of the small injection quantity of ms
No. 2 cylinder at 25 MPa
80 Small injection quantity at Indicates the final learned value IG switch: ON -0.41 to 0.36
pressure 1 - No. 3 cylinder of the small injection quantity of ms
No. 3 cylinder at 25 MPa
81 Small injection quantity at Indicates the final learned value IG switch: ON -0.41 to 0.36
pressure 1 - No. 4 cylinder of the small injection quantity of ms
No. 4 cylinder at 25 MPa
82 Small injection quantity at Indicates the final learned value IG switch: ON -0.47 to 0.43
pressure 2 - No. 1 cylinder of the small injection quantity of ms
No. 1 cylinder at 40 MPa
83 Small injection quantity at Indicates the final learned value IG switch: ON -0.47 to 0.43
pressure 2 - No. 2 cylinder of the small injection quantity of ms
No. 2 cylinder at 40 MPa
84 Small injection quantity at Indicates the final learned value IG switch: ON -0.47 to 0.43
pressure 2 - No. 3 cylinder of the small injection quantity of ms
No. 3 cylinder at 40 MPa


5 - 9 Pub. No. PTAE1228

5. DIAGNOSIS SYSTEM


(Be continued from previous page)
No. Item Meaning of the item Inspection condition Normal value
85 Small injection quantity at Indicates the final learned value IG switch: ON -0.47 to 0.43
pressure 2 - No. 4 cylinder of the small injection quantity of ms
No. 4 cylinder at 40 MPa
86 Small injection quantity at Indicates the final learned value IG switch: ON -0.29 to 0.32
pressure 3 - No. 1 cylinder of the small injection quantity of ms
No. 1 cylinder at 70 MPa
87 Small injection quantity at Indicates the final learned value IG switch: ON -0.29 to 0.32
pressure 3 - No. 2 cylinder of the small injection quantity of ms
No. 2 cylinder at 70 MPa
88 Small injection quantity at Indicates the final learned value IG switch: ON -0.29 to 0.32
pressure 3 - No. 3 cylinder of the small injection quantity of ms
No. 3 cylinder at 70 MPa
89 Small injection quantity at Indicates the final learned value IG switch: ON -0.29 to 0.32
pressure 3 - No. 4 cylinder of the small injection quantity of ms
No. 4 cylinder at 70 MPa
90 Small injection quantity at Indicates the final learned value IG switch: ON -0.13 to 0.17
pressure 4 - No. 1 cylinder of the small injection quantity of ms
No. 1 cylinder at 100 MPa
91 Small injection quantity at Indicates the final learned value IG switch: ON -0.13 to 0.17
pressure 4 - No. 2 cylinder of the small injection quantity of ms
No. 2 cylinder at 100 MPa
92 Small injection quantity at Indicates the final learned value IG switch: ON -0.13 to 0.17
pressure 4 - No. 3 cylinder of the small injection quantity of ms
No. 3 cylinder at 100 MPa
93 Small injection quantity at Indicates the final learned value IG switch: ON -0.13 to 0.17
pressure 4 - No. 4 cylinder of the small injection quantity of ms
No. 4 cylinder at 100 MPa
94 Small injection quantity at Indicates the final learned value IG switch: ON -0.16 to 0.17
pressure 5 - No. 1 cylinder of the small injection quantity of ms
No. 1 cylinder at 150 MPa
95 Small injection quantity at Indicates the final learned value IG switch: ON -0.16 to 0.17
pressure 5 - No. 2 cylinder of the small injection quantity of ms
No. 2 cylinder at 150 MPa
96 Small injection quantity at Indicates the final learned value IG switch: ON -0.16 to 0.17
pressure 5 - No. 3 cylinder of the small injection quantity of ms
No. 3 cylinder at 150 MPa
97 Small injection quantity at Indicates the final learned value IG switch: ON -0.16 to 0.17
pressure 5 - No. 4 cylinder of the small injection quantity of ms
No. 4 cylinder at 150 MPa
106 Idle speed control torque Target torque for idle speed con- Engine: After warm-up, idling 50 - 120 Nm
trol (ISC) All lights/accessories: OFF
Transmission: Neutral or P range


*: This item is indicated as follows. FF: Initial condition, 0: Non-learning state, 1: Tempo-
Note
rary learning completed status, 2: Learning completed status, 3: Non-learning state.



















Pub. No. PTAE1228 5 - 10

5. DIAGNOSIS SYSTEM


5. ACTUATOR TEST FUNCTION
The actuator test items that can be performed with the MUT III are given in the table below.
No. Inspection item Value to be determined as normal
1 Engine check lamp The engine check lamp turns ON
2 Glow lamp The glow lamp turns ON
3 Glow relay The glow plug relay ON
4 A/C relay The A/C compressor clutch makes an audi-
ble sound.
5 Condenser fan relay <Vehicles with A/C condenser fan> Drive the fan motor
15 Injector No. 1 Cut fuel to No. 1 injector
16 Injector No. 2 Cut fuel to No. 2 injector
17 Injector No. 3 Cut fuel to No. 3 injector
18 Injector No. 4 Cut fuel to No. 4 injector
19 Suction control valve Drive the suction control valve
25 EGR valve (0% open) The EGR valve fully closes
26 EGR valve (50% open) The EGR valve opens in half
27 EGR valve (100% open) The EGR valve fully opens
28 Throttle valve (0 degree open) The throttle valve fully closes
29 Throttle valve (45 degree open) The throttle valve opens roughly in half
30 Throttle valve (90 degree open) The throttle valve fully opens






















































5 - 11 Pub. No. PTAE1228