ISUZU Service manual 4JA1-4JH1-TC

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–347

Step A ction Value(s) Yes No
14 — Go to Step 15
15 Check any accessory parts which may cause electric — Remove the
16 interference. accessory parts
Was the problem found? — and verify repair
17
Is the ECM programmed with the latest software — Verify repair Go to Step 16
18 release? —
If not, download the latest software to the ECM using Go to Step 17 Go to Step 18
the “SPS (Service Programming System)”.
Was the problem solved? Verify repair —
Verify repair —
Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the injection pump assembly.
Is the action complete?

6E–348 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1650 (Symptom Code B) (Flash Code 44)
CAN Device Hang-up

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” — Go to On Board
performed? Diagnostic
—
— (OBD) System
Check
—
2 1. Connect the Tech 2. Go to Step 3 Refer to
— Diagnostic Aids
2. Review and record the failure information. — and Go to Step

3. Select “F0: Read DTC Infor As Stored By ECU” in 3
“F0: Diagnostic Trouble Codes”.
Refer to
Is the DTC P1650 (Symptom Code B) stored as Go to Step 4 Diagnostic Aids
“Present Failure”?
Verify repair Go to Step 5
3 1. Using the Tech 2, ignition “On” and engine “Off”.
Go to Step 6 Go to Step 7
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and Verify repair —
clear the DTC information. Verify repair —

3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1650 (Symptom Code B) stored in this
ignition cycle?

4 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

5 Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6 Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

7 Replace the injection pump assembly.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–349

DIAGNOSTIC TROUBLE CODE (DTC) P1651 (SYMPTOM CODE A)
(FLASH CODE 45) CAN MALFUNCTION

DIAGNOSTIC TROUBLE CODE (DTC) P1651 (SYMPTOM CODE B)
(FLASH CODE 45) CAN RECEIVES ERROR

Condition for setting the DTC and action taken when the DTC sets

Flash Code Symptom MIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
Code P1651 Code ON CAN Malfunction
The PSG (pump control unit) 1. MAB (fuel cutoff solenoid
45 A does not recognize CAN sig- valve) is operated.
nal from the CAN controller.
B ON CAN Malfunction The ECM does not read CAN 2. Desired injection quantity
signal from the PSG (pump becomes 0mg/strk.
control unit).

Circuit Description systems to communicate.

The interchange of data between the engine control Diagnostic Aids
module (ECM) and the pump control unit (PSG) is
performed via a CAN-bus system. The individual CAN- An intermittent may be caused by the following:
bus systems are connected via two interfaces and can • Poor connections.
exchange information and data. This allows control • Misrouted harness.
modules that are connected to different CAN-bus

6E–350 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

• Rubbed through wire insulation. terminals, and poor terminal to wire connection.

• Broken wire inside the insulation. • Damaged harness-Inspect the wiring harness for
Check for the following conditions: damage. If the harness appears to be OK, observe
the DTC P1651 display on the Tech2 while moving
• Poor connection at ECM and PSG-Inspect harness connectors and wiring harnesses.
connectors for backed out terminals, improper
mating, broken locks, improperly formed or damaged

Diagnostic Trouble Code (DTC) P1651 (Symptom Code A) (Flash Code 45)
CAN Malfunction

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” — Go to On Board
performed? Diagnostic
—
— (OBD) System
Check
—
2 1. Connect the Tech 2. Go to Step 3 Refer to
— Diagnostic Aids
2. Review and record the failure information. — and Go to Step

3. Select “F0: Read DTC Infor As Stored By ECU” in 3
“F0: Diagnostic Trouble Codes”.
Refer to
Is the DTC P1651 (Symptom Code A) stored as Go to Step 4 Diagnostic Aids
“Present Failure”?
Verify repair Go to Step 5
3 1. Using the Tech 2, ignition “On” and engine “Off”.
Go to Step 6 Go to Step 7
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and Verify repair —
clear the DTC information. Verify repair —

3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1651 (Symptom Code A) stored in this
ignition cycle?

4 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

5 Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6 Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

7 Replace the injection pump assembly.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–351

Diagnostic Trouble Code (DTC) P1651 (Symptom Code B) (Flash Code 45)
CAN Receives Error

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” — Go to On Board
performed? Diagnostic
—
— (OBD) System
Check

2 1. Connect the Tech 2. Go to Step 3 Refer to
Diagnostic Aids
2. Review and record the failure information. and Go to Step

3. Select “F0: Read DTC Infor As Stored By ECU” in 3
“F0: Diagnostic Trouble Codes”.
Go to Step 4 Refer to
Is the DTC P1651 (Symptom Code B) stored as Diagnostic Aids
“Present Failure”? Go to DTC and Go to Step
Chart P1650
3 1. Using the Tech 2, ignition “On” and engine “Off”. 4
(Symptom
2. Select “F1: Clear DTC Information” in “F0: Code A) Go to Step 5
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.

3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1651 (Symptom Code B) stored in this
ignition cycle?

4 Was the DTC P1650 (Symptom Code A) stored at the
same time?

5 Check for poor/faulty connection at the ECM or PSG
(pump control unit) connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?

C-57 E-6 2

100 99 1

— Verify repair Go to Step 6
—
6 Visually check the PSG (pump control unit). Go to Step 19 Go to Step 7
Was the problem found?

7 Using the DVM and check the CAN high circuit.

1. Ignition “Off”, engine “Off”.

2. Disconnect the ECM connector and PSG (pump
control unit) connector.

3. Check the circuit for short to CAN low circuit.
Was the DVM indicated specified value?

E-6
2

Repair faulty

harness and

1 No continuity Go to Step 8 verify repair

6E–352 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
8
Using the DVM and check the CAN high circuit.
Breaker box is available:

1. Ignition “Off”, engine “Off”.

2. Install the breaker box as type A. (ECM
disconnected) Ref. Page 6E-103

3. Disconnect the PSG (pump control unit)
connector.

4. Check the circuit for open or short to ground
circuit.

Was the problem found?

Breaker Box E-6
100

Breaker box is not available:

1. Ignition “Off”, engine “Off”.

2. Disconnect the PSG (pump control unit)
connector.

3. Check the circuit for open or short to ground
circuit.

Was the problem found?

C-57 E-6

100 2

Repair faulty

harness and

— verify repair Go to Step 9

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–353

Step A ction Value(s) Yes No
9
Using the DVM and check the CAN low circuit.
Breaker box is available:

1. Ignition “Off”, engine “Off”.

2. Install the breaker box as type A. (ECM
disconnected) Ref. Page 6E-103

3. Disconnect the PSG (pump control unit)
connector.

4. Check the circuit for open or short to ground
circuit.

Was the problem found?

Breaker Box E-6
99

Breaker box is not available:

1. Ignition “Off”, engine “Off”.

2. Disconnect the PSG (pump control unit)
connector.

3. Check the circuit for open or short to ground
circuit.

Was the problem found?

C-57 E-6

99 1

— Repair faulty Go to Step 10
harness and
verify repair

10 Using the DVM and check the CAN high circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the PSG (pump control unit)
connector.
3. Check the circuit for short to power supply circuit.

Was the DVM indicated battery voltage or
approximately 5V?

E-6

2

V

— Go to Step 11 Go to Step 12

6E–354 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
11
Repair the short to voltage circuit between the ECM
and PSG (pump control unit).
Is the action complete?

C-57 E-6

100 2 — Verify repair —

12 Using the DVM and check the CAN low circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the PSG (pump control unit)
connector.
3. Check the circuit for short to power supply circuit.

Was the DVM indicated battery voltage or
approximately 5V?

E-6

1

V

— Go to Step 13 Go to Step 14

13 Repair the short to voltage circuit between the ECM
and PSG (pump control unit).
Is the action complete?

C-57 E-6

99 1 — Verify repair —

14 Using the DVM and check the PSG (pump control
unit) ground circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the PSG (pump control unit)
connector.
3. Check the circuit for open circuit.
Was the problem found?

E-6

6

Repair faulty
harness and
— verify repair Go to Step 15

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–355

Step A ction Value(s) Yes No
15 — Go to Step 16
16 Check any accessory parts which may cause electric — Remove the
17 interference. accessory parts
Was the problem found? — and verify repair
18
Is the ECM programmed with the latest software — Verify repair Go to Step 17
19 release? —
If not, download the latest software to the ECM using Go to Step 18 Go to Step 19
the “SPS (Service Programming System)”.
Was the problem solved? Verify repair —
Verify repair —
Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the injection pump assembly.
Is the action complete?

6E–356 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

DIAGNOSTIC TROUBLE CODE (DTC) P1690 (SYMPTOM CODE 4)
(FLASH CODE 77) CHECK ENGINE LAMP (MIL) CIRCUIT VOLTAGE LOW

DIAGNOSTIC TROUBLE CODE (DTC) P1690 (SYMPTOM CODE 8)
(FLASH CODE 77) CHECK ENGINE LAMP (MIL) CIRCUIT VOLTAGE HIGH

Condition for setting the DTC and action taken when the DTC sets

Flash Code Symptom MIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
Code P1690 Code OFF Check Engine Lamp (MIL) No fail-safe function.
4 Check engine lamp circuit
77 Circuit Voltage Low open or short to ground cir-
8 OFF Check Engine Lamp (MIL) cuit.
Check engine lamp circuit
Circuit Voltage High short to ground circuit.

Circuit Description Diagnostic Aids

The Check Engine Lamp (Malfunction Indicator Lamp An intermittent may be caused by the following:
=MIL) should always be illuminated and steady with • Poor connections.
ignition “On”. Ignition feed voltage is supplied to the • Misrouted harness.
Check Engine Lamp bulb through the meter fuse. The • Rubbed through wire insulation.
ECM turns the Check Engine Lamp “On” by grounding • Broken wire inside the insulation.
the check engine lamp driver circuit for a certain time.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–357

Check for the following conditions: • Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
• Poor connection at ECM-Inspect harness connectors the “Check Engine Lamp” display on the Tech2 while
for backed out terminals, improper mating, broken moving connectors and wiring harnesses. A change
locks, improperly formed or damaged terminals, and in the display will indicate the location of the fault.
poor terminal to wire connection.

Diagnostic Trouble Code (DTC) P1690 (Symptom Code 4) (Flash Code 77)
Check Engine Lamp (MIL) Circuit Voltage Low

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? — Diagnostic

— (OBD) System
— Check
—
2 1. Connect the Tech 2. — Go to Step 3 Refer to
Diagnostic Aids
2. Review and record the failure information. and Go to Step

3. Select “F0: Read DTC Infor As Stored By ECU” in 3
“F0: Diagnostic Trouble Codes”.
Go to Step 4 Refer to
Is the DTC P1690 (Symptom Code 4) stored as Diagnostic Aids
“Present Failure”? and Go to Step

3 1. Using the Tech 2, ignition “On” and engine “Off”. 4

2. Select “F1: Clear DTC Information” in “F0: Go to Step 5 Go to Step 6
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information. Go to Step 9 Go to Step 7

3. Operate the vehicle and monitor the “F0: Read Verify repair Go to Step 7
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1690 (Symptom Code 4) stored in this
ignition cycle?

4 1. Ignition “On”, engine “Off”.

2. Check the “Check Engine” lamp.
Does the lamp turn “On”?

5 1. Ignition “On”, engine “Off”.

2. Check the “Check Engine” lamp.
Does the lamp turn “Off”?

6 Check the “Check Engine” lamp bulb.
If the bulb is burnt out, repair as necessary.
Was the problem found?

7 Check for poor/faulty connection at the meter
connector and ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?

C-56 42

17 B-24

— Verify repair Go to Step 8

6E–358 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
8
Using the DVM and check the “Check Engine” lamp
circuit.
Breaker box is available:

1. Ignition “Off”, engine “Off”.

2. Install the breaker box as type A. (ECM
disconnected) Ref. Page 6E-103

3. Remove the meter connector.

4. Check the circuit for open or short to ground
circuit.

Was the problem found?

Breaker Box B-24
42

Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Remove the meter connector.
4. Check the circuit for open or short to ground
circuit.

Was the problem found?

C-56

42

B-24

17 — Repair faulty Go to Step 9
— harness and
9 Is the ECM programmed with the latest software verify repair
release?
If not, download the latest software to the ECM using Verify repair Go to Step 10
the “SPS (Service Programming System)”.
Was the problem solved?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–359

Step A ction Value(s) Yes No
10 — Verify repair
Replace the ECM. —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6E–360 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1690 (Symptom Code 8) (Flash Code 77)
Check Engine Lamp (MIL) Circuit Voltage High

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” — Go to On Board
performed? Diagnostic
—
— (OBD) System
Check
—
2 1. Connect the Tech 2. Go to Step 3 Refer to
— Diagnostic Aids
2. Review and record the failure information. and Go to Step

3. Select “F0: Read DTC Infor As Stored By ECU” in 3
“F0: Diagnostic Trouble Codes”.
Refer to
Is the DTC P1690 (Symptom Code 8) stored as Go to Step 4 Diagnostic Aids
“Present Failure”?
Verify repair Go to Step 5
3 1. Using the Tech 2, ignition “On” and engine “Off”.
Go to Step 6 —
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and Verify repair —
clear the DTC information.

3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1690 (Symptom Code 8) stored in this
ignition cycle?

4 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

5 Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6 Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–361

SYMPTOM DIAGNOSIS

PRELIMINARY CHECKS Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
Before using this section, perform the “On-Board when the malfunction occurs is a good indication that
Diagnostic (OBD) System Check” and verify all of the there is a fault in the circuit being monitored.
following items: Using Tech 2 to help detect intermittent conditions. The
Tech 2 have several features that can be used to
• The engine control module (ECM) and check engine located an intermittent condition. Use the following
lamp (MIL=malfunction indicator lamp are operating features to find intermittent faults:
correctly.
To check for loss of diagnostic code memory,
• There are no Diagnostic Trouble Code(s) stored. disconnect the MAF sensor and idle the engine until the
check engine lamp (MIL=malfunction indicator lamp)
• Tech 2 data is within normal operating range. Refer to comes on. Diagnostic Trouble Code P0100 should be
Typical Scan Data Values. stored and kept in memory when the ignition is turned
OFF.
• Verify the customer complaint and locate the correct If not, the ECM is faulty. When this test is completed,
symptom in the table of contents. Perform the make sure that you clear the Diagnostic Trouble Code
procedure included in the symptom chart. P0100 from memory.

VISUAL/PHYSICAL CHECK An intermittent check engine lamp (MIL=malfunction
indicator lamp) with no stored Diagnostic Trouble Code
Several of the symptom procedures call for a careful may be caused by the following:
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable • Check engine lamp (MIL=malfunction indicator lamp)
time. This check should include the following items: wire to ECM short to ground.

• ECM grounds for cleanliness, tightness and proper • Poor ECM grounds. Refer to the ECM wiring
location. diagrams.

• Vacuum hoses for splits, kinks, and proper Check for improper installation of electrical options such
connection. Check thoroughly for any type of leak or as light, cellular phones, etc. Check all wires from ECM
restriction. to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
• Air intake ducts for collapsed or damaged areas. clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).
• Air leaks at throttle body mounting area, mass air flow
(MAF) sensor and intake manifold sealing surfaces. If problem has not been found, refer to ECM connector
symptom tables.
• Wiring for proper connections, pinches and cuts.
• Check the “Broadcast Code” of the ECM, and
INTERMITTENT compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
Important: An intermittent problem may or may not turn determine if an update to the ECM's reprogrammable
on the check engine lamp (MIL=malfunction indicator memory has been released.
lamp) or store a Diagnostic Trouble Code. Do NOT use
the Diagnostic Trouble Code (DTC) charts for This identifies the contents of the reprogrammable
intermittent problems. software and calibration contained in the ECM.
The fault must be present to locate the problem. If the “Broadcast Code” is not the most current
Most intermittent problems are cased by faulty electrical available, it is advisable to reprogram the ECM's
connections or wiring. Perform a careful visual/physical EEPROM memory, which may either help identify a
check for the following conditions. hard-to find problem or may fix the problem.
The Service Programming System (SPS) will not allow
• Poor mating of the connector halves or a terminal not incorrect software programming or incorrect calibration
fully seated in the connector (backed out). changes.

• Improperly formed or damaged terminal.

• All connector terminals in the problem circuit should
be carefully checked for proper contact tension.

• Poor terminal-to-wire connection. This requires
removing the terminal form the connector body to
check.

• Check engine lamp (MIL=malfunction indicator lamp)
wire to ECM shorted to ground.

• Poor ECM grounds. Refer to the ECM wiring
diagrams.

6E–362 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

ENGINE CRANKS BUT WILL NOT RUN

DEFINITIONS: Engine cranks, but will not run. (The engine never start.)
NOTE: The vehicle with immobilizer system, this system may be activated. Check the immobilizer system diagnosis.

Step A ction Value(s) Yes No
1 — Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? — Diagnostic
—
(OBD) System
Check

2 1. Perform a bulletin search. Verify repair Go to Step 3
2. If a bulletin that addresses the symptom is found, Go to Step 4
correct the condition as instructed in the bulletin. Go to Visual /
physical Check
Was a bulletin found that addresses the symptom?
3 Was a visually/physical check performed?

4 Is the fuel amount enough?

Add fuel to the
— Go to Step 5 tank

5 Is the customer using the incorrect fuel type? Diesel fuel Replace with
only diesel fuel
Go to Step 6

6 Check the “ECM” fuse (10A) and “Engine” fuse (15A). — Verify repair Go to Step 7
If the fuse is burnt out, repair as necessary.
Was the problem found?

7 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger. — Verify repair Go to Step 8
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

8 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 9
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

9 1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Neutral Switch” in the data display. — Verify repair Go to Step 10
Does the Tech 2 indicate correct “Neutral Switch”
status depending on any shift positions?
If a problem is found, repair as necessary.
Was the problem found?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–363

Step A ction Value(s) Yes No
10 Verify repair Go to Step 11
Remove the CKP sensor from the flywheel housing —
11 and check for the following conditions. Verify repair Go to Step 12
—
12 • Objects sticking the CKP sensor. — Go to Step 13 Go to Step 14
13 —
14 • Objects sticking the CKP sensor pulser. — Verify repair —
15 If a problem is found, repair as necessary.
Was the problem found? — Verify repair Go to Step 16
16 —
Check the CKP sensor harness for the following Verify repair Go to Step 17
conditions. Verify repair Go to Step 18

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good CKP sensor and recheck.
Was the problem solved?

Replace the CKP sensor.
Is the action complete?

Check the exhaust system for a possible restriction.

• Damaged or collapsed pipes or catalytic converter.

• Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?

Visually/physically inspect for the following conditions.

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

Replace the fuel filter.
Was the problem solved?

6E–364 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
17
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 18

18 Check the engine compression pressure for each
cylinders.
If a problem is found, repair as necessary.
Was the problem found?

More than 2.1 Verify repair Go to Step 19
Mpa (21.0 kg/

cm2)

19 If the injection pump was replaced, are the timing
gears or injection pump correctly installed?

Repair as

— Go to Step 20 necessary

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–365

Step A ction Value(s) Yes No
20
1. Review all diagnostic procedures within this table. — Verify repair Go to Step 21
21 — Verify repair Go to Step 22
22 2. If all procedures have been completed and no
malfunctions have been found, review/inspect the — Go to Step 23 Go to Step 24
23 following:
— Verify repair —
24 • Visual/physical inspection — Verify repair —

• Tech 2 data

• All electrical connections within a suspected circuit
and/or system

Was a problem found?

Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

Replace the injection pump assembly.
Is the action complete?

6E–366 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

HARD START SYMPTOM

DEFINITIONS: Engine cranks, but does not start for a long time. Does eventually start, or may start and then
immediately stall.

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, — Verify repair Go to Step 3
correct the condition as instructed in the bulletin. Go to Visual /
Go to Step 4 physical Check
Was a bulletin found that addresses the symptom? Replace with
Go to Step 6
3 Was a visually/physical check performed? diesel fuel

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger. — Verify repair Go to Step 6
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

6 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 7
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.

2. Check the displayed value. — Verify repair Go to Step 8
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?

8 1. Using the Tech 2, display the FT sensor value.

2. Check the displayed value. — Go to Step 20 Go to Step 9
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?

9 1. Using the Tech 2, ignition “On”.

2. Monitor the “Glow Time Relay” in the data display. — Go to Step 20 Go to Step 10
Does the Tech 2 indicate correct “Glow Time Relay”
status depending on the time from ignition switch
“On”?
If a problem is found, repair as necessary.
Was the problem found?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–367

Step A ction Value(s) Yes No
10
1. Using the Tech 2, ignition “On”.

2. Monitor the “Glow Time Relay” in the data display
and then, does the supply voltage correctly supply
to the glow plug?

Repair voltage
supply circuit
— Go to Step 11 and verify repair

11 Check the glow plugs for continuity.
If a problem is found, repair as necessary.
Was a problem found?

12 Check the exhaust system for a possible restriction. — Verify repair Go to Step 12
— Verify repair Go to Step 13
• Damaged or collapsed pipes or catalytic converter.
— Verify repair Go to Step 14
• Internal muffler failure. — Verify repair Go to Step 15
If a problem is found, repair as necessary.
Was a problem found?

13 Visually/physically inspect for the following conditions.

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

14 Replace the fuel filter.
Was the problem solved?

6E–368 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
15
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 16

16 Remove the injection nozzles from the engine and
check for the following conditions.

• Improper splay condition.

• Operating pressure is incorrect.
If a problem is found, repair as necessary.
Was the problem found?

1st Stage 2nd Stage

4JA1-TC Approximatly Approximatly
19.0 Mpa 33.5 Mpa

4JH1-TC Approximatly Approximatly Replace the
19.5 Mpa 33.8 Mpa injection nozzle
— and verify repair Go to Step 17

17 Check the engine compression pressure for each
cylinders.
If a problem is found, repair as necessary.
Was the problem found?

More than 2.1 Verify repair Go to Step 18
Mpa

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–369

Step A ction Value(s) Yes No
18
Check the inlet/exhaust valve clearance for each
valves.
Are the valve clearances within the specified value?

0.4mm at cold Adjust and
verify repair
(I n/Ex ) Go to Step 19

19 1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected circuit — Verify repair Go to Step 20
and/or system

Was a problem found?

20 Is the ECM programmed with the latest software — Verify repair Go to Step 21
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

21 Substitute a known good ECM and recheck. — Go to Step 22 Go to Step 23
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

22 Replace the ECM. — Verify repair —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

23 Replace the injection pump assembly. — Verify repair —
Is the action complete?

6E–370 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTOM

DEFINITIONS: Engine runs unevenly at idle. If severe, rpm
the engine or vehicle may shake. Engine idle speed
may vary in RPM. Either condition may be severe
enough to stall the engine.

X

Rough Idle Stall
time

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search. — Verify repair Go to Step 3
Go to Visual /
2. If a bulletin that addresses the symptom is found, Go to Step 4 physical Check
correct the condition as instructed in the bulletin. Replace with
Go to Step 5
Was a bulletin found that addresses the symptom? diesel fuel

3 Was a visually/physical check performed?

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 1. Check for incorrect idle speed. Ensure that the
following conditions are present.

• Engine fully warm.

• Accessories are “OFF”. Desired Go to Step 7 Go to Step 6
Engine Idle
2. Using a Tech 2, monitor “Desired Engine Idle Speed ± 25
Speed” and “Engine Speed”.
rpm
Is the “Engine Speed” within the specified values?

6 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger. — Verify repair Go to Step 7
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

7 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 8
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–371

Step A ction Value(s) Yes No
8 —
1. Using the Tech 2, ignition “On” and engine “Off”. Verify repair Go to Step 9
9 —
2. Monitor the “Neutral Switch” in the data display. Verify repair Go to Step 10
10 Does the Tech 2 indicate correct “Neutral Switch” —
status depending on any shift positions? — Verify repair Go to Step 11
11 If a problem is found, repair as necessary. — Go to Step 16 Go to Step 12
12 Was the problem found? Verify repair Go to Step 13
13 —
1. Using the Tech 2, ignition “On” and engine “Run”. — Verify repair Go to Step 14
14 —
15 2. Monitor the “A/C Information Switch” in the data — Go to Step 15 Go to Step 35
16 display.
Verify repair —
Does the Tech 2 indicate correct “A/C Information
Switch” status depending on A/C switch position? Go to Step 21 Go to Step 17
If a problem is found, repair as necessary.
Was the problem found?

1. Using the Tech 2, display the ECT sensor and IAT
sensor value.

2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?

1. Using the Tech 2, ignition “On” and engine “Run”.

2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation?

Remove the MAF & IAT sensor assembly and check
for the following conditions.

• Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?

Check the MAF sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?

Replace the MAF & IAT sensor assembly.
Is the action complete?

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.

Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?

6E–372 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
17
1. Using the Tech 2, ignition “On” and engine “Off”. — Verify repair Go to Step 18
18
2. Monitor the “Pedal/Throttle Position” and “Idle — Verify repair Go to Step 19
19 Switch” in the data display. — Go to Step 20 Go to Step 36
20 — Verify repair
21 3. Adjust the accelerator cable or TPS within 0% to —
100%. — Verify repair
22 Go to Step 22
Was the problem solved? — Verify repair
23 — Go to Step 24 Go to Step 23
24 Check the TPS harness for the following conditions. — Verify repair Go to Step 25

• Check for poor connector connection. —

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good TPS and recheck.
Was the problem solved?

Replace the TPS.
Is the action complete?

Remove the CKP sensor from the flywheel housing
and check for the following conditions.

• Objects sticking the CKP sensor.

• Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found?

Check the CKP sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

SubstituteaknowngoodCKPsensorandrecheck.
Was the problem solved?

Replace the CKP sensor.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–373

Step A ction Value(s) Yes No
25
1. Using the Tech 2 and ignition “On” and engine
“Run”.

2. Monitor the following parameters in the data
display.

• “Desired Injection Quantity” & “Injection Quantity”

• “Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?

When idling or part-throttle

High Desired

Actual

Low

Time

— Go to Step 29 Go to Step 26

6E–374 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
26
Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or excessive carbon
deposit.

Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
• Solenoid 95%: EGR Valve Open
• Solenoid 5%: EGR Valve Close

Vacuum Pump:

1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.

2. Apply vacuum pressure.

• Vacuum Apply: EGR Valve Open

• Vacuum Release: EGR Valve Close

Vacuum Pump Small Window

If a problem is found, repair as necessary. — Verify repair Go to Step 27
Was the problem found? — Verify repair Go to Step 28

27 Check the exhaust system for a possible restriction. —
—
• Damaged or collapsed pipes or catalytic converter.

• Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?

28 Visually/physically inspect for the following conditions.

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or Verify repair Go to Step 29
icing, such as the customer is using an incorrect Verify repair Go to Step 30
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

29 Replace the fuel filter.
Was the problem solved?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–375

Step A ction Value(s) Yes No
30
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 32

31 Remove the injection nozzles from the engine and
check for the following conditions.

• Improper splay condition.

• Operating pressure is incorrect.
If a problem is found, repair as necessary.
Was the problem found?

1st Stage 2nd Stage

4JA1-TC Approximatly Approximatly Replace the
4JH1-TC 19.0 Mpa 33.5 Mpa injection nozzle
— and verify repair Go to Step 32
Approximatly Approximatly
19.5 Mpa 33.8 Mpa

32 Check the engine compression pressure for each
cylinders. Each cylinder must be evenly.
If a problem is found, repair as necessary.
Was the problem found?

More than 2.1 Verify repair Go to Step 33
Mpa

6E–376 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
33
Check the inlet/exhaust valve clearance for each
valves.
Are the valve clearances within the specified value?

0.4mm at cold Adjust and
verify repair
(I n/Ex ) Go to Step 34

34 1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected circuit — Verify repair Go to Step 35
and/or system

Was a problem found?

35 Is the ECM programmed with the latest software — Verify repair Go to Step 36
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

36 Substitute a known good ECM and recheck. — Go to Step 37 Go to Step 38
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

37 Replace the ECM. — Verify repair —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

38 Replace the injection pump assembly. — Verify repair —
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–377

SURGES AND/OR CHUGS SYMPTOM

DEFINITIONS: Engine power variation under steady rpm
throttle or cruise. Feels like the vehicle speeds up and
slows down with no charge in the accelerator pedal.

Surge

time

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search. — Verify repair Go to Step 3
Go to Visual /
2. If a bulletin that addresses the symptom is found, Go to Step 4 physical Check
correct the condition as instructed in the bulletin. Replace with
Go to Step 5
Was a bulletin found that addresses the symptom? diesel fuel

3 Was a visually/physical check performed?

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger. — Verify repair Go to Step 6
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

6 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 7
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

7 1. Using the Tech 2, ignition “On” and engine “Run”. — Verify repair Go to Step 8

2. Monitor the “A/C Information Switch” in the data
display.

Does the Tech 2 indicate correct “A/C Information
Switch” status depending on A/C switch position?
If a problem is found, repair as necessary.
Was the problem found?

6E–378 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
8
1. Using the Tech 2, display the ECT sensor and IAT — Verify repair Go to Step 9
9 sensor value. — Go to Step 14 Go to Step 10
10 — Verify repair Go to Step 11
11 2. Check the displayed value.
Does the Tech 2 indicate correct temperature — Verify repair Go to Step 12
12 depending on engine condition? — Go to Step 13 Go to Step 29
13 If a problem is found, repair as necessary. — Verify repair
14 Was the problem found? —
— Go to Step 19
15 1. Using the Tech 2, ignition “On” and engine “Run”. Go to Step 15
— Verify repair
16 2. Monitor the “Mass Air Flow” in the data display. Go to Step 16
Does the Tech 2 indicate correct “Mass Air Flow” — Verify repair
17 depending on accelerator pedal operation? — Go to Step 18 Go to Step 17
18 — Verify repair Go to Step 29
Remove the MAF & IAT sensor assembly and check
for the following conditions. —

• Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?

Check the MAF sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?

Replace the MAF & IAT sensor assembly.
Is the action complete?

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.

Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.

3. Adjust the accelerator cable or TPS within 0% to
100%.

Was the problem solved?

Check the TPS harness for the following conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good TPS and recheck.
Was the problem solved?

Replace the TPS.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–379

Step A ction Value(s) Yes No
19 Verify repair Go to Step 20
Remove the CKP sensor from the flywheel housing —
20 and check for the following conditions. Verify repair Go to Step 21
—
21 • Objects sticking the CKP sensor. — Go to Step 22 Go to Step 23
22 —
23 • Objects sticking the CKP sensor pulser. Verify repair —
If a problem is found, repair as necessary.
Was the problem found?

Check the CKP sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good CKP sensor and recheck.
Was the problem solved?

Replace the CKP sensor.
Is the action complete?

1. Using the Tech 2 and ignition “On” and engine
“Run”.

2. Monitor the following parameters in the data
display.

• “Desired Injection Quantity” & “Injection Quantity”

• “Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?

When idling or part-throttle When accelerated

High Desired High Desired

Actual Actual
Low Low
Time — Go to Step 25 Go to Step 24
Time

6E–380 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
24
Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or excessive carbon
deposit.

Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
• Solenoid 95%: EGR Valve Open
• Solenoid 5%: EGR Valve Close

Vacuum Pump:

1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.

2. Apply vacuum pressure.

• Vacuum Apply: EGR Valve Open

• Vacuum Release: EGR Valve Close

Vacuum Pump Small Window

If a problem is found, repair as necessary. — Verify repair Go to Step 25
Was the problem found?
—
25 Visually/physically inspect for the following conditions. —

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or Verify repair Go to Step 26
icing, such as the customer is using an incorrect Verify repair Go to Step 27
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

26 Replace the fuel filter.
Was the problem solved?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–381

Step A ction Value(s) Yes No
27
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 28

28 1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected circuit — Verify repair Go to Step 29
and/or system

Was a problem found?

29 Is the ECM programmed with the latest software — Verify repair Go to Step 30
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

30 Substitute a known good ECM and recheck. — Go to Step 31 Go to Step 32
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

31 Replace the ECM. — Verify repair —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6E–382 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
32 — Verify repair —
Replace the injection pump assembly.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–383

HESITATION, SAG, STUMBLE SYMPTOM

DEFINITIONS: Momentary lack of response as the rpm Stumble
accelerator is pushed down. Can occur at any vehicle Sug
speed. Usually most pronounced when first trying to
make the vehicle move, as from a stop sign. May cause
the engine to stall if severe enough.

Hesitation
time

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search. — Verify repair Go to Step 3
Go to Visual /
2. If a bulletin that addresses the symptom is found, Go to Step 4 physical Check
correct the condition as instructed in the bulletin. Replace with
Go to Step 5
Was a bulletin found that addresses the symptom? diesel fuel

3 Was a visually/physical check performed?

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 Check the torque converter clutch (TCC) for proper — Verify repair Go to Step 6
operation (if A/T model). If a problem is found, repair
as necessary.
Was a problem found?

6 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in — Verify repair Go to Step 7
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

7 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 8
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

6E–384 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
8
1. Using the Tech 2, display the ECT sensor and IAT — Verify repair Go to Step 9
9 sensor value. — Go to Step 14 Go to Step 10
10 — Verify repair Go to Step 11
11 2. Check the displayed value.
Does the Tech 2 indicate correct temperature — Verify repair Go to Step 12
12 depending on engine condition? — Go to Step 13 Go to Step 31
13 If a problem is found, repair as necessary. — Verify repair
14 Was the problem found? —
— Go to Step 19
15 1. Using the Tech 2, ignition “On” and engine “Run”. Go to Step 15
— Verify repair
16 2. Monitor the “Mass Air Flow” in the data display. Go to Step 16
Does the Tech 2 indicate correct “Mass Air Flow” — Verify repair
17 depending on accelerator pedal operation? — Go to Step 18 Go to Step 17
18 — Verify repair Go to Step 31
Remove the MAF & IAT sensor assembly and check
for the following conditions. —

• Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?

Check the MAF sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?

Replace the MAF & IAT sensor assembly.
Is the action complete?

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.

Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.

3. Adjust the accelerator cable or TPS within 0% to
100%.

Was the problem solved?

Check the TPS harness for the following conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good TPS and recheck.
Was the problem solved?

Replace the TPS.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–385

Step A ction Value(s) Yes No
19 Verify repair Go to Step 20
Remove the CKP sensor from the flywheel housing —
20 and check for the following conditions. Verify repair Go to Step 21
—
21 • Objects sticking the CKP sensor. — Go to Step 22 Go to Step 23
22 —
23 • Objects sticking the CKP sensor pulser. Verify repair —
If a problem is found, repair as necessary.
Was the problem found?

Check the CKP sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good CKP sensor and recheck.
Was the problem solved?

Replace the CKP sensor.
Is the action complete?

1. Using the Tech 2 and ignition “On” and engine
“Run”.

2. Monitor the following parameters in the data
display.

• “Desired Injection Quantity” & “Injection Quantity”

• “Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?

When idling or part-throttle When accelerated

High Desired High Desired

Actual Actual — Go to Step 27 Go to Step 24
Low Low Time

Time

6E–386 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
24
Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or excessive carbon
deposit.

Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
• Solenoid 95%: EGR Valve Open
• Solenoid 5%: EGR Valve Close

Vacuum Pump:

1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.

2. Apply vacuum pressure.

• Vacuum Apply: EGR Valve Open

• Vacuum Release: EGR Valve Close

Vacuum Pump Small Window

If a problem is found, repair as necessary. — Verify repair Go to Step 25
Was the problem found? — Verify repair Go to Step 26

25 Check the exhaust system for a possible restriction. —
—
• Damaged or collapsed pipes or catalytic converter.

• Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?

26 Visually/physically inspect for the following conditions.

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or Verify repair Go to Step 27
icing, such as the customer is using an incorrect Verify repair Go to Step 28
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

27 Replace the fuel filter.
Was the problem solved?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–387

Step A ction Value(s) Yes No
28
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 29

29 1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected circuit — Verify repair Go to Step 30
and/or system

Was a problem found?

30 Is the ECM programmed with the latest software — Verify repair Go to Step 31
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

31 Substitute a known good ECM and recheck. — Go to Step 32 Go to Step 33
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

32 Replace the ECM. — Verify repair —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

6E–388 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
33 — Verify repair —
Replace the injection pump assembly.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–389

CUTS OUT, MISSES SYMPTOM

DEFINITIONS: Steady pulsation or jerking that follows rpm
engine speed; usually more pronounced as engine load
increases.

time

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search. — Verify repair Go to Step 3
Go to Visual /
2. If a bulletin that addresses the symptom is found, Go to Step 4 physical Check
correct the condition as instructed in the bulletin. Replace with
Go to Step 5
Was a bulletin found that addresses the symptom? diesel fuel

3 Was a visually/physical check performed?

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger. — Verify repair Go to Step 6
Check for objects blocking the turbocharger
compressor

wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?

6 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 7
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

6E–390 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
7
1. Using the Tech 2, perform test drive.

2. Monitor the “Vehicle Speed” in the data display.
Does the Tech 2 indicate correct “Vehicle Speed”
depending on driving speed?

When constant vehicle speed

High Correct Speed

Unstable Data — Go to Step 11 Go to Step 8

Low — Verify repair Go to Step 9
—
Time — Go to Step 10 Go to Step 31
—
8 Check the VSS harness for the following conditions. Verify repair —
—
• Check for poor connector connection. Go to Step 16 Go to Step 12
—
• Check for misrouted harness. — Verify repair Go to Step 13
• Check for any accessory parts which may cause —
Verify repair Go to Step 14
electric interference.
If a problem is found, repair as necessary. Go to Step 15 Go to Step 31
Was a problem found?
Verify repair —
9 Substitute a known good VSS and recheck.
Was the problem solved?

10 Replace the VSS assembly.
Is the action complete?

11 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.

Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation?

12 Remove the MAF & IAT sensor assembly and check
for the following conditions.

• Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?

13 Check the MAF sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

14 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?

15 Replace the MAF & IAT sensor assembly.
Is the action complete?

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–391

Step A ction Value(s) Yes No
16 Go to Step 21 Go to Step 17
1. Using the Tech 2, ignition “On” and engine “Off”. — Verify repair Go to Step 18
17
2. Monitor the “Pedal/Throttle Position” and “Idle — Verify repair Go to Step 19
18 Switch” in the data display.
— Go to Step 20 Go to Step 31
19 Does the Tech 2 indicate correct “Pedal/Throttle —
20 Position” from 0% to 100% and correct “Idle Switch” — Verify repair —
21 status depending on accelerator pedal operation?
— Verify repair Go to Step 22
22 1. Using the Tech 2, ignition “On” and engine “Off”.
— Verify repair Go to Step 23
23 2. Monitor the “Pedal/Throttle Position” and “Idle —
24 Switch” in the data display. — Go to Step 24 Go to Step 25

3. Adjust the accelerator cable or TPS within 0% to Verify repair —
100%.

Was the problem solved?

Check the TPS harness for the following conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good TPS and recheck.
Was the problem solved?

Replace the TPS.
Is the action complete?

Remove the CKP sensor from the flywheel housing
and check for the following conditions.

• Objects sticking the CKP sensor.

• Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found?

Check the CKP sensor harness for the following
conditions.

• Check for poor connector connection.

• Check for misrouted harness.

• Check for any accessory parts which may cause
electric interference.

If a problem is found, repair as necessary.
Was a problem found?

Substitute a known good CKP sensor and recheck.
Was the problem solved?

Replace the CKP sensor.
Is the action complete?

6E–392 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
25
1. Using the Tech 2 and ignition “On” and engine
“Run”.

2. Monitor the following parameters in the data
display.

• “Desired Injection Quantity” & “Injection Quantity”

• “Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?

When idling or part-throttle

High Desired

Actual

Low

Time

— Go to Step 29 Go to Step 26

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–393

Step A ction Value(s) Yes No
26
Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or excessive carbon
deposit.

Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
• Solenoid 95%: EGR Valve Open
• Solenoid 5%: EGR Valve Close

Vacuum Pump:

1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.

2. Apply vacuum pressure.

• Vacuum Apply: EGR Valve Open

• Vacuum Release: EGR Valve Close

Vacuum Pump Small Window

If a problem is found, repair as necessary. — Verify repair Go to Step 27
Was the problem found?
—
27 Visually/physically inspect for the following conditions. —

• Restrict fuel supply system. Check for a pinched
fuel hose/pipe.

• Check for a condition that causes fuel waxing or Verify repair Go to Step 28
icing, such as the customer is using an incorrect Verify repair Go to Step 29
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was a problem found?

28 Replace the fuel filter.
Was the problem solved?

6E–394 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Step A ction Value(s) Yes No
29
Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.

• Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
extended maintenance interval.

• Check for a condition that causes fuel waxing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mixed with the
fuel.

If a problem is found, repair as necessary.
Was the problem found?

Replace the
eye bolt with
gauze filter and
— verify repair Go to Step 30

30 1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected circuit — Verify repair Go to Step 31
and/or system

Was a problem found?

31 Is the ECM programmed with the latest software — Verify repair Go to Step 32
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

32 Substitute a known good ECM and recheck. — Go to Step 33 Go to Step 34
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

33 Replace the ECM. — Verify repair —
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–395

Step A ction Value(s) Yes No
34 — Verify repair —
Replace the injection pump assembly.
Is the action complete?

6E–396 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS

LACK OF POWER, SLUGGISH OR SPONGY SYMPTOM

DEFINITIONS: Engine delivers less than expected power. Attempting part-throttle acceleration results in little or no
increase in vehicle speed.

Step A ction Value(s) Yes No
1 Go to Step 2
Was the “On-Board Diagnostic (OBD) System Check” Go to On Board
performed? Diagnostic

— (OBD) System
Check

2 1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, — Verify repair Go to Step 3
correct the condition as instructed in the bulletin. Go to Visual /
Go to Step 4 physical Check
Was a bulletin found that addresses the symptom? Replace with
Go to Step 5
3 Was a visually/physical check performed? diesel fuel

—

4 Is the customer using the incorrect fuel type? Diesel fuel
only

5 Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in
the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum — Verify repair Go to Step 6
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

6 Check the ECM & PSG grounds to verify that they are — Verify repair Go to Step 7
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.

2. Check the displayed value. — Verify repair Go to Step 8
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?

8 1. Using the Tech 2, display the FT sensor value.

2. Check the displayed value. — Go to Step 29 Go to Step 9
Does the Tech 2 indicate correct temperature Go to Step 14 Go to Step 10
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?

9 1. Using the Tech 2, ignition “On” and engine “Run”. —

2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation?