ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –259
6 Check for poor/faulty connection of the PSG (pump
control unit) ground at the cylinder body. If a poor/
faulty connection is found, repair as necessary.
Was the problem found?
— Verify repair Go to Step 7
7 Replace the injection pump assembly. Is the action complete? —Verify repair —
Step Action Value(s) Yes No
E-10

6E–260 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0561 (SYMPTOM CODE A)
(FLASH CODE 18) IGNITION SWITCH CIRCUIT MALFUNCTION
DIAGNOSTIC TROUBLE CODE (DTC) P0561 (SYMPTOM CODE B)
(FLASH CODE 18) IGNITION SWITCH CIRCUIT MALFUNCTION
Condition for setting the DTC and action taken when the DTC sets
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
18 P0561 A OFF Ignitio n Switch Circuit Ma l-
functionThe ECM recognized ignition
switch turn o ff signa l during
ECM is activated.ECM stops engine.
B OFF Ignitio n Switch Circuit Ma l-
function Ignitio n switch circuit is mal-
function.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–261
Circuit Description
The ECM monitors the ignition switch signal on the feed
terminal to the ECM. If the ignition switch signal with
malfunction, DTC P0561 (Symptom Code A) or DTC
P0561 (Symptom Code B) will be stored.
Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Misrouted harness.Rubbed through wire insulation.
Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM-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 “Ignition Status” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0561 (Symptom Code A) (Flash Code 18)
Ignition Switch Circuit Malfunction
Diagnostic Trouble Code (DTC) P0561 (Symptom Code B) (Flash Code 18)
Ignition Switch Circuit 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 P0561 (Symptom Code A) or P0561
(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 P0561 (Symptom Code A) or P0561
(Symptom Code B)stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check the “Engine fuse (10A)”.
If the fuse is burnt out, repair as necessary.
Was the problem found?—Verify repair Go to Step 5

6E –262 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
5 Using the DVM and check the ignition power feed
circuit.
Breaker box is available:
1. Ignition “Off ”, engine “Off ”.
2. Install the breaker box as type A. (ECM disconnected)
3. 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 ECM 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 6
6 Check the ignition switch. If a poor/faulty connection is found, repair as
necessary.
Was the problem found? —Verify repair Go to Step 7
7 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 8
Step Action Value(s) Yes No
39
Breaker Box



C-107


39
9
C-56
C-107

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–263
8 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— Step Action Value(s) Yes No

6E–264 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0602 CONTROL MODULE
PROGRAMMING ERROR
Condition for setting the DTC and action taken when the DTC sets
Circuit Description & Diagnostic Aids
The replacement ECM must be programmed by Service
Programming System (SPS). Because, the serviceECM does not programmed.
When the service ECM is used without SPS, DTC
P0602 will appear.
Diagnostic Trouble Code (DTC) P0602 Control Module Programming Error
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
- P0602 - - Control Module Programming
Erro rECM memo ry are a erro r. Engine control disable d.
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 P0602 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
3 Download the latest software to the ECM using the
“SPS (Service Programming System)”.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–265
DIAGNOSTIC TROUBLE CODE (DTC) P0606 (SYMPTOM CODE A)
(FLASH CODE 28) ECU MALFUNCTION
DIAGNOSTIC TROUBLE CODE (DTC) P0606 (SYMPTOM CODE B)
(FLASH CODE 28) ECU MALFUNCTION
Condition for setting the DTC and action taken when the DTC sets
Circuit Description & Diagnostic Aids
If the ECM inside (IC, circuit, memory, etc,) failed, DTC
P0606 (Symptom Code A) or P0606 (Symptom Code B)
will be stored.
Diagnostic Trouble Code (DTC) P0606 (Symptom Code A) (Flash Code 28) ECU
Malfunction
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
28 P0606 A ON ECM Malfunctio n Gate Array communica tio n
error.1. MAB (fuel cutoff solenoid
valve) is operated.
2. Desired injection quantity
becomes 0mg/strk.
B ON ECM Malfunctio n 1. Thro ttle po sitio n is be lo w
1%.
2. De sire d injection qua ntity is
more than 0mg/strk.
3. Engine speed is more than
2000rpm. MAB (fue l cutoff so le no id
valve) is operated.
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 P0606 (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 P0606 (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

6E–266 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
5 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— Step Action Value(s) Yes No

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–267
Diagnostic Trouble Code (DTC) P0606 (Symptom Code B) (Flash Code 28) ECU
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 P0606 (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 P0606 (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–268 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0645 (SYMPTOM CODE 4)
(FLASH CODE 46) A/C COMPRESSOR RELAY CIRCUIT VOLTAGE LOW
DIAGNOSTIC TROUBLE CODE (DTC) P0645 (SYMPTOM CODE 8)
(FLASH CODE 46) A/C COMPRESSOR RELAY CIRCUIT VOLTAGE HIGH
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The voltage on the coil of the A/C compressor is
supplied by the ECM main relay. The ECM switches A/C
compressor relay to operate A/C compressor depends
on the A/C request signal and certain setting conditions.
Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Misrouted harness.
Rubbed through wire insulation.
Broken wire inside the insulation.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
46 P0645 4 ON A/C Co mpressor Re lay Circuit
Voltage LowA/C co mpre sso r re la y circuit
open or short to ground cir-
cuit.No fa il-sa fe fun ctio n.
8 ON A/C Co mpressor Re lay Circuit
Vo lta ge High A/C co mpre sso r re la y circuit
short to voltage circuit.