2004 ISUZU TF SERIES ECU

6E–148 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0105 (Symptom Code 7) (Flash Code 34)
Vacuum Pressure Sensor Voltage Supply Circuit High Input
Step Action Value(s) Yes No
1 Was 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 P0105 (Symptom Code 7) 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
c l e a r t h e D T C i n f o r m a t i o n .
3. Operate the vehicle and monitor the "F0: Read
DTC Infor As Stored By ECU" in the "F0:
Diagnostic Trouble Codes".
Was the DTC P0105 (Symptom Code 7) 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 vacuum
pressure sensor or ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?
- Verify repair Go to Step 5
5 V i s u a l l y c h e c k t h e v a c u u m p r e s s u r e s e n s o r .
Was the problem found? - Go to Step 8Go to Step 6
6 Using the DVM and check the vacuum pressure
sensor power supply circuit.
1. Ignition "On", engine "Off".
2. Disconnect the vacuum pressure sensor
connector.
3. Check the circuit for short to battery voltage
circuit.
Was the DVM indicated specified value?
Approx imately
5.0V
Go to Step 8Go to Step 7
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6E–150 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0105 (Symptom Code 9) (Flash Code 34)
Vacuum Pressure Sensor Voltage Supply Circuit Low Input
Step Action Value(s) Yes No
1 Was 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 P0105 (Symptom Code 9) 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
c l e a r t h e D T C i n f o r m a t i o n .
3. Operate the vehicle and monitor the "F0: Read
DTC Infor As Stored By ECU" in the "F0:
Diagnostic Trouble Codes".
Was the DTC P0105 (Symptom Code 9) 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 vacuum
pressure sensor or ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?
- Verify repair Go to Step 5
5 V i s u a l l y c h e c k t h e v a c u u m p r e s s u r e s e n s o r .
Was the problem found? - Go to Step 10Go to Step 6
6 Using the DVM and check the vacuum pressure
sensor power supply circuit.
1. Ignition "On", engine "Off".
2. Disconnect the vacuum pressure sensor
connector.
3 . C h e c k t h e c i r c u i t f o r s h o r t t o g r o u n d c i r c u i t .
Was the DVM indicated specified value?
Approx imately
5.0V
Go to Step 10Go to Step 7
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –153
The ECM supplies 5 volts signal to the IAT sensor
through resisters in the ECM and measures the voltage.
The signal voltage will be high when the air temperature
is cold, and it will be low when the air temperature is
hot.
The output voltage ex cessively high or low, DTC P0110
(Symptom Code 1) or P0110 (Symptom Code 2) 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 “Intake Air Temperature ” display on the Tech2
while moving connectors and wiring harness related
to the sensor.
Diagnostic Trouble Code (DTC) P0110 (Sy mptom Code 1) (Flash Code 23)
Intake Air Temperature (IAT) Sensor Circuit High Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0110 (Symptom Code 1) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0110 (Symptom Code 1) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the IAT sensor or ECM 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 IAT sensor. Was the problem found? —Go to Step 12 Go to Step 6
92
84
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C-116
C-57(B)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –157
Diagnostic Trouble Code (DTC) P0110 (Sy mptom Code 2) (Flash Code 23)
Intake Air Temperature (IAT) Sensor Circuit Low Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0110 (Symptom Code 2) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0110 (Symptom Code 2) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the IAT sensor or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Remove the MAF & IAT sensor assembly and visually check.
Was the problem found? —Go to Step 8 Go to Step 6
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84
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –161
a high resistance.
The ECM supplies 5 volts signal to the ECT sensor
through resisters in the ECM and measures the voltage.
The signal voltage will be high when the engine
temperature is cold, and it will be low when the engine
temperature is hot.
The output voltage ex cessively high or low, DTC P0115
(Symptom Code 1) or P0115 (Symptom Code 2) 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 “Coolant Temperature ” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0115 (Sy mptom Code 1) (Flash Code 14)
Engine Coolant Temperature Sensor Circuit High Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0115 (Symptom Code 1) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0115 (Symptom Code 1) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the ECT sensor or ECM 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 ECT sensor. Was the problem found? —Go to Step 12 Go to Step 6
932
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89 E-41
C-57(B)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –165
Diagnostic Trouble Code (DTC) P0115 (Sy mptom Code 2) (Flash Code 14)
Engine Coolant Temperature Sensor Circuit Low Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0115 (Symptom Code 2) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0115 (Symptom Code 2) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the ECT sensor or ECM 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 ECT sensor. Was the problem found? —Go to Step 8 Go to Step 6
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89 E-41
C-57(B)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–169
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0180 (Sy mptom Code B) (Flash Code 15) Fuel
Temperature Sensor Circuit Range/Performance
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 P0180 (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 P0180 (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—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–171
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
When the ignition switch is turned “Off”, the fuel
solenoid valve (MAB) signal is supplied from the ECM to
the PSG. This signal is the command for the PSG to turn
“Off” the engine.
If the MAB signal circuit is short to voltage circuit or
short to ground circuit, DTC P0215 (Symptom Code B)
or P0215 (Symptom Code C) 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.
Diagnostic Trouble Code (DTC) P0215 (Sy mptom Code A) (Flash Code 52) Fuel
Cutoff Solenoid Valve Malfunction
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
52 P0215 A ON Fuel Cutoff Solenoid Valve
Malfunctio n1. Ignition key switch off.
2. Engine spe e d is be lo w
1500rpm.
3. Vehicle speed is below
1.5km/h.
4. PSG (pump co ntrol unit)
recognizes MAB (fuel cutoff
solenoid valve) signal from
the ECM, but the MAB
could not operate. 1. MAB (fuel cutoff solenoid
valve) is operated.
2. Desired injection quantity
becomes 0mg/strk.
B ON Fuel Cutoff Solenoid Valve
Circuit High InputECM does not command
MAB (fue l cutoff so le no id
valve) signal to the PSG
(pump co ntrol unit), but PSG
detected MAB signal line cir-
cuit is high level.Engine do es not sta rt.
C ON Fuel Cutoff Solenoid Valve
Always Active1. Ignition key switch off.
2. Engine spe e d is be lo w
1500rpm.
3. Vehicle speed is below
1.5km/h.
4. PSG (pump co ntrol unit)
does not recognize MAB
(fue l cutoff so le no id v alv e )
signa l from the ECM. 1. MAB (fuel cutoff solenoid
valve) is operated.
2. Desired injection quantity
becomes 0mg/strk.
D ON Fuel Cutoff Solenoid Valve
Malfunctio n1. Ignition key switch off.
2. CAN contro lle r doe s no t
operate Bus-off.No fa il-sa fe fun ctio n.
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 P0215 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3