check engine ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–343
Poor connection at ECM and PSG-Inspect harness
connectors for backed out terminals, improper
mating, broken locks, improperly formed or damaged
terminals, and poor terminal to wire connection.Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the DTC P1650 display on the Tech2 while moving
connectors and wiring harnesses.
Diagnostic Trouble Code (DTC) P1650 (Symptom Code A) (Flash Code 44)
CAN Device Offline
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1650 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
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 P1650 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 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?
—Verify repair Go to Step 5
5 Visually check the PSG (pump control unit).
Was the problem found? —Go to Step 18Go to Step 6
6 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?
No continuity Go to Step 7Repair faulty
harness and
verify repair
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6E–344 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
7 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 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?
—Repair faulty
harness and
verify repair Go to Step 8 Step Action Value(s) Yes No
E-6100Breaker Box




1002 C-57 E-6

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–345
8 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 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?
—Repair faulty
harness and
verify repair Go to Step 9
9 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?
—Go to Step 10Go to Step 11 Step Action Value(s) Yes No
E-699Breaker Box





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6E–346 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
10 Repair the short to voltage circuit between the ECM
and PSG (pump control unit).
Is the action complete?
—Verify repair—
11 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?
—Go to Step 12Go to Step 13
12 Repair the short to voltage circuit between the ECM
and PSG (pump control unit).
Is the action complete?
—Verify repair—
13 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?
—Repair faulty
harness and
verify repair Go to Step 14 Step Action Value(s) Yes No
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–347
14 Check any accessory parts which may cause electric
interference.
Was the problem found?—Remove the
accessory parts
and verify repair Go to Step 15
15 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?—Verify repair Go to Step 16
16 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. —Go to Step 17Go to Step 18
17 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.—Verify repair—
18 Replace the injection pump assembly.
Is the action complete?—Verify repair— Step Action Value(s) Yes No

6E–348 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1650 (Symptom Code B) (Flash Code 44)
CAN Device Hang-up
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1650 (Symptom Code B) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
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 P1650 (Symptom Code B) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
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?—Verify repair Go to Step 5
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. —Go to Step 6Go to Step 7
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.—Verify repair—
7 Replace the injection pump assembly.
Is the action complete?—Verify repair—

6E–350 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Rubbed through wire insulation.
Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM and PSG-Inspect harness
connectors for backed out terminals, improper
mating, broken locks, improperly formed or damagedterminals, and poor terminal to wire connection.
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the DTC P1651 display on the Tech2 while moving
connectors and wiring harnesses.
Diagnostic Trouble Code (DTC) P1651 (Symptom Code A) (Flash Code 45)
CAN Malfunction
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1651 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
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 A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
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?—Verify repair Go to Step 5
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. —Go to Step 6Go to Step 7
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.—Verify repair—
7 Replace the injection pump assembly.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–351
Diagnostic Trouble Code (DTC) P1651 (Symptom Code B) (Flash Code 45)
CAN Receives Error
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1651 (Symptom Code B) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
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?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Was the DTC P1650 (Symptom Code A) stored at the
same time?
—Go to DTC
Chart P1650
(Symptom
Code A)Go to Step 5
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?
—Verify repair Go to Step 6
6 Visually check the PSG (pump control unit).
Was the problem found? —Go to Step 19Go to Step 7
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?
No continuity Go to Step 8Repair faulty
harness and
verify repair
1009912
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6E–352 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
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 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?
—Repair faulty
harness and
verify repair Go to Step 9 Step Action Value(s) Yes No
E-6100Breaker Box




1002 C-57 E-6

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–353
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 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?
—Repair faulty
harness and
verify repair Go to Step 10
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?
—Go to Step 11 Go to Step 12 Step Action Value(s) Yes No
E-699Breaker Box




991 C-57 E-6
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