2004 ISUZU TF SERIES air condition

6E–242 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
4 Perform test drive and check the speed meter.
Does the speed meter indicate correct vehicle speed.—Go to Step 5Go to Step 6
5 Perform test drive and use the Tech 2.
Monitor the “Vehicle Speed” in the data display.
Does the Tech 2 indicate correct vehicle speed as
same as the speed meter indication in the instrument
panel?—Go to Step 15Go to Step 7
6 Remove the VSS from the housing case and visually
check.
Was the problem found? —Go to Step 8Go to Step 7
7 Using the DVM and check the VSS signal.
1. Ignition “On”, vehicle “Run (lift up)”.
2. Measure the VSS output voltage at sensor, TCM
(A/T 2WD), meter and ECM.
Does the tester indicate specified value?
If a oscilloscope is available, monitor the VSS signal
at each connector connection. Does the oscilloscope
indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
15Refer the table
8 Replace the VSS.
Is the action complete?—Verify repair
9 Replace the TCM.
Is the action complete?
IMPORTANT: The replacement TCM must be
programmed. “SPS (Service Programming System)
is necessary.” —Verify repair— Step Action Value(s) Yes No
Me asure ment Position Vo lta ge (V)
(AC Range)If No
Go od
VSS terminal 3 & GND Approximately 6.0
V at 20km/hGo to
Step 8
TCM C94 conne ctor 10 &
GND (A/T 2WD)Go to
Step 9
Meter B24 connector 9 &
GNDGo to
St e p 1 0
Meter B24 connector 10 &
GNDGo to
St e p 1 2
ECM C56 connector 68 &
GNDGo to
St e p 1 3
Ve hicle Spee d Sensor (VSS) Refe re nce Wav e Fo rm
0V
Mea sure me nt Terminal: 68(+) GND(-)
Mea sure me nt Scale: 5V/div 50ms/div
Measurement Condition: Approximately 20km/h

6E–246 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the VSS signal.
1. Ignition “On”, vehicle “Run (lift up)”.
2. Measure the VSS output voltage at sensor, TCM
(A/T 2WD), meter and ECM.
Does the tester indicate specified value?
If a oscilloscope is available, monitor the VSS signal
at each connector connection. Does the oscilloscope
indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
10Refer the table
8 Replace the VSS.
Is the action complete?—Verify repair
9 Replace the TCM.
Is the action complete?
IMPORTANT: The replacement TCM must be
programmed. “SPS (Service Programming System)
is necessary.” —Verify repair—
10 Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?—Remove the
accessory parts
and verify repair Go to Step 12
11 Replace the speed meter.
Is the action complete?—Verify repair—
12 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 13 Step Action Value(s) Yes No
Me asure ment Position Vo lta ge (V)
(AC Range)If No
Go od
VSS terminal 3 & GND Approximately 6.0
V at 20km/hGo to
Step 8
TCM te rmina l A10 & B5
(A/T 2WD)Go to
Step 9
Meter B24 connector 9 &
GNDGo to
St e p 1 0
Meter B24 connector 10 &
GNDGo to
Step 11
ECM C56 connector 68 &
GNDGo to
St e p 1 0
Ve hicle Spee d Sensor (VSS) Refe re nce Wav e Fo rm
0V
Mea sure me nt Terminal: 68(+) GND(-)
Mea sure me nt Scale: 5V/div 50ms/div
Measurement Condition: Approximately 20km/h

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –249
7 Check for poor/faulty connection at the ECM and
other connectors. If a poor/faulty connection is found,
repair the faulty terminal.
Was the problem found?
— Verify repair Go to Step 9
8 Remove the VSS from the housing case and visually
check.
Was the problem found? —Go to Step 10 Go to Step 9
9 Using the DVM and check the VSS signal. 1. Ignition “On ”, vehicle “Run (lift up) ”.
2. Measure the VSS output voltage at sensor, TCM (A/T 2WD), meter and ECM.
Does the tester indicate specified value?
If a oscilloscope is available, monitor the VSS si gnal
at each connector connection. Does the oscilloscope
indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
17 Refer the table
10 Replace the VSS. Is the action complete? —Verify repair
Step Action Value(s) Yes No
68
C-56
Me asure ment Position Vo lta ge (V)
(AC Range) If No
Go od
VSS terminal 3 & GND Approximately 6.0 V at 20km/h Go to
St e p 1 0
TCM C94 conne ctor 10 &
GND (A/T 2WD) Go to
Step 11
Meter B24 connector 9 &
GND Go to
St e p 1 2
Meter B24 connector 10 &
GND Go to
St e p 1 4
ECM C56 connector 68 &
GND Go to
St e p 1 5
Ve hicle Spee d Sensor (VSS) Refe re nce Wav e Fo rm
0V 
Mea sure me nt Terminal: 68(+) GND(-)
Mea sure me nt Scale: 5V/div 50ms/div
Measurement Condition: Approximately 20km/h

6E–254 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
or low, DTC P0560 (Symptom Code A) 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 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 “System Voltage” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0560 (Symptom Code 1) (Flash Code 35)
System Voltage Too High
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 P0560 (Symptom Code 1) 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 P0560 (Symptom Code 1) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Was the battery jump start cable incorrectly
connecting?—Verify
procedure Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “System Voltage” in the data display.
3. Load the electrical system by turning on the
headlights, etc..
Does the Tech 2 indicate correct ignition voltage? 10 - 14.5V Go to Step 6Check the
charging
system
6 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 7

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–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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–269
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 DTC P0645 display on the Tech2 while moving
connectors and wiring harnesses.
Diagnostic Trouble Code (DTC) P0645 (Sy mptom Code 4) (Flash Code 46) A/C
Compressor Relay Circuit Voltage Low
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 P0645 (Symptom Code 4) 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 P0645 (Symptom Code 4) 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 A/C
compressor relay or ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?
—Verify repair Go to Step 5
5 Using the DVM and check the A/C compressor relay.
1. Ignition “Off”, engine “Off”.
2. Remove the A/C compressor relay from the relay
box .
3. Check the relay coil.
Was the DVM indicated specified value?
120-150
Go to Step 6Replace A/C
compressor
relay and verify
repair
C-56
X-14








A/C Compressor Relay