check engine ISUZU TF SERIES 2004 Workshop Manual

6E–292 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
11 Using the DVM and check the TPS ground 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 TPS connector.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the TPS connector and ECM
connector.
3. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 14
12 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 13Go to Step 14
13 Replace the TPS.
Is the action complete?—Verify repair—
14 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 15
15 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
E-2249Breaker Box




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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–293
Diagnostic Trouble Code (DTC) P1120 (Sy mptom Code 7) (Flash Code 21)
Pedal/Throttle Position Sensor Voltage Supply Circuit High Input
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 P1120 (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
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 P1120 (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 TPS 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 TPS.
Was the problem found? —Go to Step 8Go to Step 6
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6E–294 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the TPS power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for short to ground circuit.
Was the DVM indicated specified value?
Approx imately
5.0V Go to Step 12Go to Step 7
7 Repair the short to battery voltage circuit between the
ECM and TPS.
Was the problem solved?
—Verify repair Go to Step 8
8 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 9Go to Step 10
9 Replace the TPS.
Is the action complete?—Verify repair—
10 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 11
11 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
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–295
Diagnostic Trouble Code (DTC) P1120 (Sy mptom Code 9) (Flash Code 21)
Pedal/Throttle Position Sensor Voltage Supply Circuit Low Input
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 P1120 (Symptom Code 9) stored as
“Present Failure”?—Go to Step 3Refer to
Diagno stic 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 P1120 (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 TPS 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 TPS.
Was the problem found? —Go to Step 10Go to Step 6
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6E–296 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the TPS power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for short to battery voltage
circuit.
Was the DVM indicated specified value?
Approx imately
5.0V Go to Step 10Go to Step 7
7 Using the DVM and check the TPS power supply
circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the TPS connector and ECM
connector.
3. Check the circuit for short to TPS ground circuit.
Was the DVM indicated specified value?
No continuity Go to Step 9Go to Step 8
8 Repair the circuit for short to TPS ground circuit.
Is the action complete?—Verify repair—
9 Repair the short to ground circuit between the ECM
and TPS.
Was the problem solved?
—Verify repair Go to Step 12
10 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 11Go to Step 12
11 Replace the TPS.
Is the action complete?—Verify repair— Step Action Value(s) Yes No
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6E–298 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1120 (Sy mptom Code D) (Flash Code 21)
Pedal/Throttle Position Sensor Brake Switch 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 P1120 (Symptom Code D) 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 P1120 (Symptom Code D) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Visually check the TPS.
Check for the following conditions.
Accelerator pedal sticking.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position”
from 0% to 100% depending on accelerator pedal
operation?—Go to Step 7Go to Step 6
6 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?—Verify repair Go to Step 11
7 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Brake Switch 1” and “Brake Switch 2”
in the data display.
Does the Tech 2 indicate “Inactive” when the brake
pedal was not stepped on?—Go to Step 13Go to Step 8
8 Adjust the brake switch.
Was the problem solved?—Verify repair Go to Step 9
9 Substitute a known good brake switch and recheck.
Was the problem solved?—Go to Step 10Go to Step 13
10 Replace the brake switch.
Is the action complete?—Verify repair—
11 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 12Go to Step 13
12 Replace the TPS.
Is the action complete?—Verify repair—

6E–300 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1120 (Symptom Code E) (Flash Code 21)
Pedal/Throttle Position Sensor Idle Position Switch 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 P1120 (Symptom Code E) 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 P1120 (Symptom Code E) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Visually check the TPS.
Was the problem found? —Go to Step 8Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position”
from 0% to 100% depending on accelerator pedal
operation?—Go to Step 7Go to Step 6Go
to Step 6
6 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?—Verify repair Go to Step 8
7 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Idle Switch” in the data display.
Does the Tech 2 indicate “Inactive” when the
accelerator pedal was stepped on?—Go to Step 10Go to Step 8
8 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 9Go to Step 10
9 Replace the TPS.
Is the action complete?—Verify repair—
10 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 11

6E–302 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1173 (SYMPTOM CODE 3)
(FLASH CODE 22) FUEL REDUCTION CAUSED BY HIGH COOLANT
TEMPERATURE
DIAGNOSTIC TROUBLE CODE (DTC) P1173 (SYMPTOM CODE 7)
(FLASH CODE 22) FUEL REDUCTION CAUSED BY HIGH FUEL TEMPERATURE
DIAGNOSTIC TROUBLE CODE (DTC) P1173 (SYMPTOM CODE A)
(FLASH CODE 22) FUEL REDUCTION CAUSED BY LOW FUEL TEMPERATURE
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine coolant temperature (ECT) sensor is
installed on the coolant stream. High coolant
temperature produces a low 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 low when the engine temperature
is hot.
The fuel temperature sensor is assembled inside of the
pump control unit (PSG). The signal of fuel temperature
is sent via the CAN-bus from the PSG to ECM.
If the engine coolant temperature is ex cessively high
condition, DTC P1173 (Symptom Code 3) will be stored.
If the fuel temperature is ex cessively high or low
condition, DTC P1173 (Symptom Code 7) or P1173
(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 “Coolant Temperature” or “Fuel Temperature”
display on the Tech2 while moving connectors and
wiring harness related to the sensor.
Diagnostic Trouble Code (DTC) P1173 (Symptom Code 3) (Flash Code 22) Fuel
Reduction Caused By High Coolant Temperature
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
22 P1173 3 OFF Fuel Reduction Caused By
High Coolant TemperatureExcessive high engine cool-
ant temperature is detected.No fa il-sa fe fun ctio n.
7 OFF Fuel Re ductio n Ca used By
High Fuel TemperatureFuel te mpe rature is mo re tha n
100 de g. C.PSG (pump contro l unit) con-
tro ls fuel inje ctio n qua ntity
based on engine speed and
fuel temperature.
A OFF Fuel Re ductio n Ca used By
Low Fuel TemperatureExcessive low fuel tempera-
ture is de te cted.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 P1173 (Symptom Code 3) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–303
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 P1173 (Symptom Code 3) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check the engine overheat condition.
Was the problem found?
—Repair the
cause of
overheat and
verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Coolant Temperature” in the data
display.
Does the Tech 2 indicate correct “Coolant
Temperature” depending on warm up time?—Go to Step 9Go to Step 6
6 Using the DVM and check the ECT sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect ECT sensor connector.
3. Measure the resistance of ECT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 9Go to Step 7
7 Substitute a known good ECT sensor assembly and
recheck.
Was the problem solved?—Go to Step 8Go to Step 9
8 Replace the ECT sensor.
Is the action complete?—Verify repair—
9 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 10 Step Action Value(s) Yes No
Temperature (°C) Re sista nce (
) (Appro xima te ly )
-20 16100
0 5760
20 2370
40 1080
60 537
80 290
100 161
120 95
1 2
ECT Sensor
1 2

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–305
Diagnostic Trouble Code (DTC) P1173 (Symptom Code 7) (Flash Code 22) Fuel
Reduction Caused By High Fuel Temperature
Diagnostic Trouble Code (DTC) P1173 (Sy mptom Code A) (Flash Code 22) Fuel
Reduction Caused By Low Fuel Temperature
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 P1173 (Symptom Code 7) or P1173
(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 P1173 (Symptom Code 7) or P1173
(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—