fuel type ISUZU TF SERIES 2004 Repair Manual

6E-134 3.5L ENGINE DRIVEABILITY AND EMISSIONS Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P0171 B O2 Sensor System Too Lean
(Bank 1) - -
44
P0174 B O2 Sensor System Too Lean
(Bank 2) 1. No DTC relating to MAF sensor, IAT sensor,
ECT sensor, TPS, CMP sensor, CKP sensor,
VSS, injector control circuit, ignition control
circuit, O2 sensor circuit low voltage & high
voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is more than 600rpm.
3. Intake air temperature is more than 50
C.
4. Engine coolant temperature is between 35
C
and 120
C.
5. Engine load is more than 20.
6. EVAP purge solenoid valve on-duty is below
100%.
7. Air-fuel ratio correction volume is more than
150% for 20 seconds. No fail-safe function. Air fuel ratio correction volume
is between 50% and 150% for
5 seconds. 1. Sensor harness open or short to ground
circuit.
2. O2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. IAC valve malfunction.
6. Low fuel pressure.
7. Injector malfunction.
8. ECM malfunction.
- -
P0172 B O2 Sensor System Too Rich
(Bank 1) - -
45
P0175 B O2 Sensor System Too Rich
(Bank 2) 1. No DTC relating to MAF sensor, IAT sensor,
ECT sensor, TPS, CMP sensor, CKP sensor,
VSS, injector control circuit, ignition control
circuit, O2 sensor circuit low voltage & high
voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is more than 600rpm.
3. Intake air temperature is more than 50
C.
4. Engine coolant temperature is between 35
C
and 120
C.
5. Engine load is more than 20.
6. EVAP purge solenoid valve on-duty is below
100%.
7. Air-fuel ratio correction volume is below 50%
for 20 seconds. No fail-safe function. Air fuel ratio correction volume
is between 50% and 150% for
5 seconds. 1. Sensor harness open or short to ground
circuit.
2. O2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. AC valve malfunction.
6. Low fuel pressure.
7. Injector malfunction.
8. EVAP purge solenoid valve malfunction.
9. Ignition system malfunction.
10. Spark plug malfunction.
11. ECM malfunction. - -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-135
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P1171 D Fuel Supply System Lean
During Power Enrichment
(Bank 1) B21/
B22/
-
44
P1172 D Fuel Supply System Lean
During Power Enrichment
(Bank 2) 1. No DTC relating to MAF sensor, IAT sensor,
ECT sensor, TPS, CMP sensor, CKP sensor,
VSS, injector control circuit, ignition control
circuit, O2 sensor circuit low voltage & high
voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is between 1000rpm and
6000rpm.
3. Intake air temperature is below 70
C.
4. Engine coolant temperature is between 30
C
and 120
C.
5. Engine load is between 150 and 255.
6. Throttle position output is more than 2.22V
and fluctuation is below 0.28V.
7. Except fuel cut operation.
8. O2 sensor output voltage below 250mV for 10
seconds. No fail-safe function.
O2 sensor output voltage is
more than 520mV for 5
seconds.
1. Sensor harness open or short to ground
circuit.
2. O2 sensor malfunction.
3. MAF sensor output is incorrect. 4. Air intake
line malfunction.
5. IAC valve malfunction.
6. Low fuel pressure.
7. Injector malfunction.
8. ECM malfunction.
B23/
B24 -
P0201 A Injector 1 Control Circuit
A36 - P0202 A Injector 2 Control Circuit
B3 - P0203 A Injector 3 Control Circuit
A35 - P0204 A Injector 4 Control Circuit
B4 - P0205 A Injector 5 Control Circuit
A34 -
31
P0206 A Injector 6 Control Circuit 1. No DTC relating to CMP sensor and CKP
sensor.
2. Under sequential injection.
3. Injection pulse is between 2.5ms and 7.5 ms.
4. Except fuel cut operation.
5. Engine speed is between 600rpm and
2000rpm.
6. 30 injection signals are not detected
consecutively. No fail-safe function. 30 injection signals are
detected consecutively. 1. Injector harness open circuit, short to ground
or short to voltage.
2. Injector malfunction.
3. ECM malfunction.
B5 -

6E-136 3.5L ENGINE DRIVEABILITY AND EMISSIONS Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P0336 B Crankshaft Position Sensor
Circuit Range/Performance
(58X) 1. No DTC relating to CMP sensor.
2. Engine speed is below 2000rpm.
3. Extra or missing pulse is detected
consecutively. 1. CKP sensor harness open circuit, short to
ground or short to voltage.
2. Poor connector connection.
3. CKP sensor malfunction.
4. Pulse sensing gap incorrect.
5. Electrical interference.
6. Magnetic interference.
7. ECM malfunction. A23/
A24/
A25 P0122/
P0337
29
P0337 B Crankshaft Position Sensor
Circuit No Signal (58X) 1. No DTC relating to CKP sensor.
2. Engine speed is below 2000rpm.
3. Incorrect pulse is detected consecutively. No fail-safe function.
Correct pulse is detected
consecutively.

1. CKP sensor harness open circuit, short to
ground or short to voltage.
2. CMP sensor signal circuit short to ground
circuit.
3. TPS & CMP sensor power supply circuit short
to ground.
4. Poor connector connection.
5. CKP sensor malfunction.
6. Pulse sensing gap incorrect.
7. Electrical interference.
8. Magnetic interference.
9. ECM malfunction. A23/
A24/
A25 P0112/
P0336
P0341 B Camshaft Position Sensor
Circuit Range/Performance 1. Engine speed below 2000rpm.
2. No crankshaft position sensor DTC P0336 or
P0337.
3. Incorrect pulse is detected consecutively. 1. CMP sensor harness open circuit, short to
ground or short to voltage.
2. Poor connector connection.
3. CMP sensor malfunction.
4. Pulse sensing gap incorrect.
5. Electrical interference.
6. Magnetic interference.
7. ECM malfunction. B27/
B28/
B39 P0103/
P0113/
P0123/
P0342
41
P0342 B Camshaft Position Sensor
Circuit No Signal 1. No DTC relating to CKP sensor.
2. Engine speed is below 2000rpm.
3. No pulse is detected consecutively. Fuel cut is operated at high
engine speed.
Correct pulse is detected
consecutively.

1. CMP sensor harness open circuit, short to
ground or short to voltage.
2. Poor connector connection.
3. CMP sensor malfunction.
4. Pulse sensing gap incorrect.
5. Electrical interference.
6. Magnetic interference.
7. ECM malfunction. B27/
B28/
B39 P0103/
P0113/
P0123/
P0341
or
P0122

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-137
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P0351 A Ignition 1 Control Circuit
A32 - P0352 A Ignition 2 Control Circuit
B7 - P0353 A Ignition 3 Control Circuit
A31 - P0354 A Ignition 4 Control Circuit
B8 - P0355 A Ignition 5 Control Circuit
A30 -
42
P0356 A Ignition 6 Control Circuit 1. No DTC relating to CMP sensor and CKP
sensor.
2. Engine speed is between 250rpm and 850
rpm.
3. 10 ignition signals are not detected
consecutively. Fuel cut is operated more than
2000rpm. 10 ignition signals are detected
consecutively. 1. Ignition coil harness open circuit, short to
ground or short to voltage.
2. Ignition coil malfunction.
3. ECM malfunction.
B9 -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-139
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC 24 P0500 B Vehicle Speed Sensor Circuit
Range/Performance 1. Engine speed is below 5000rpm.
2. Under fuel cut operation.
3. Vehicle speed sensor output is below 1km/h.
Above conditions are met for 4 seconds. The ECM use 10km/h
condition as substitute. Vehicle speed sensor output is
more than 2km/h. 1. Sensor harness open circuit, short to ground
circuit or short to voltage circuit.
2. Poor connector connection.
3. Electrical interference.
4. Magnetic interference.
5. VSS malfunction.
6. ECM malfunction. B32 -
P0562 D System Voltage Low Battery voltage is below 6V for more than 20
seconds. 1. Battery power feed harness open circuit or
short to ground circuit.
2. ECM ground harness open or poor
connection.
3. Poor connector connection.
4. Battery malfunction.
5. Charge system malfunction.
6. ECM malfunction. - -
66
P0563 A System Voltage High Battery voltage is above 16V for more than 20
seconds. No fail-safe function. Battery voltage is between 6V
and 16V.
1. Charge system malfunction.
2. Battery jump start cable misconnect.
3. ECM malfunction. - - 51 P0601 A Control Module Memory
Checksum ECM memory area error. Engine control disabled. Memory are is OK.
1. ECM malfunction. - -
P0602 - ECU Programming Error ECM memory area error. Engine control disabled. Memory are is OK.
1. ECM is not programmed. - -

6E-140 3.5L ENGINE DRIVEABILITY AND EMISSIONS Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P1508 B Idle Air Control System
Low/Closed 1. No DTC relating to MAF sensor, IAT sensor,
ECT sensor, TPS, CMP sensor, CKP sensor,
VSS and system voltage.
2. Engine speed is between 675rpm and
6000rpm.
3. Engine coolant temperature is more than
75
C.
4. Intake air temperature is between -10
C and
80
C.
5. Vehicle is stopping.
6. Small amount of intake air through the idle air
control valve. (Idle air control valve is sticking
at close position.) Above conditions are met
for 2 seconds. 1. IAC valve harness open circuit, short to
ground circuit or short to voltage circuit.
2. Poor connector connection.
3. IAC valve malfunction.
4. IAC valve is sticking at close position.
5. ECM malfunction. B13/
B14/
B16/
B17 -
22
P1509 B Idle Air Control System
High/Open 1. No DTC relating to MAF sensor, IAT sensor,
ECT sensor, TPS, CMP sensor, CKP sensor,
VSS and system voltage.
2. Engine speed is between 675rpm and
6000rpm.
3. Engine coolant temperature more than 75
C.
4. Intake air temperature is between -10
C and
80
C.
5. Vehicle is stopping.
6. Large amount of intake air through the idle air
control valve. (Idle air control valve is sticking
at open position.) Above conditions are met
for 2 seconds. Fuel cut is operated at high idle
speed.
Correct amount of air intake
through the idle air control
valve. (Correct movement of
the idle air control valve.)

1. IAC valve harness open circuit, short to
ground circuit or short to voltage circuit.
2. Poor connector connection.
3. IAC valve malfunction.
4. IAC valve is sticking at open position.
5. ECM malfunction. B13/
B14/
B16/
B17 - 65 P1601 D CAN BUS Off CAN BUS off condition is detected consecutively.
CAN BUS on condition is
detected consecutively for 2
seconds. 1. ECM and TCM communication circuit open,
short to ground or short to voltage.
2. Electrical interference.
3. ECM malfunction.
4. TCM malfunction. A10/
A11 - 67 U2104 D CAN BUS Reset Counter
Overrun 1. No DTC CAN BUS Off.
2. CAN valid counter does not change for 2
seconds. Torque reduction control is
disable.
CAN valid counter changes
consecutively for 2 seconds. 1. ECM and TCM communication circuit open,
short to ground or short to voltage.
2. Electrical interference.
3. ECM malfunction.
4. TCM malfunction. A10/
A11 P1767/
U2104 (AT)

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-183
DIAGNOSTIC TROUBLE CODE (DTC) P0122 (FLASH CODE 21) THROTTLE
POSITION SENSOR CIRCUIT LOW INPUT



RUW46EMF000101

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
21 P0122 A Throttle Position
Sensor Low Input TPS output voltage is below 0.24V. The ECM uses default throttle
position value based on mass air
flow and engine speed.

CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from below 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is used by the Engine Control Module
(ECM) for fuel control and many of the ECM-controlled
outputs.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the throttle position display on the Tech 2 while
moving connectors and wiring harnesses related to
the TPS. A change in the display will indicate the
location of the fault.
If DTC P0122 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E-188 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0123 (FLASH CODE 21) THROTTLE
POSITION SENSOR CIRCUIT HIGH INPUT



RUW46EMF000101

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
21 P0123 A Throttle Position
Sensor High Input TPS output voltage is more than 4.56V. The ECM uses default throttle
position value based on mass air
flow and engine speed.

CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from about 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is one of the most important inputs
used by the Engine Control Module (ECM) for fuel
control and many of the ECM-controlled outputs.
DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the TPS display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
 Faulty TPS –With the ignition key “ON," engine
“OFF," observe the TPS display on the Tech 2 while
slowly depressing the accelerator to wide open
throttle. If a voltage over 4.56 volts is seen at any
point in normal accelerator travel, replace the TPS.
If DTC P0123 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E-194 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0131 A O2 Sensor Circuit Low
Voltage (Bank 1
Sensor 1) 15
P0151 A O2 Sensor Circuit Low
Voltage (Bank 2
Sensor 1) 1. No DTC relating to ECT sensor, CMP sensor, CKP sensor,
VSS, injector control circuit, ignition control circuit and O2
sensor circuit no activity (bank 1 & 2).
2. Engine speed is between 1000rpm and 4000rpm.
3. Engine coolant temperature is between 70
C and 110
C.
4. Vehicle speed is between 0km/h and 120km/h.
5. Engine load is between 80% and 160%.
6. Throttle position fluctuation is below 0.28V.
7. O2 sensor bank 1 or bank 2 output voltage is more than
400mV for 50 seconds. "Open Loop" fuel control.

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal high and signal low circuits. The
ECM constantly monitors the HO2S signal during
“closed loop" operation and compensates for a rich o
r
lean condition by decreasing or increasing injector pulse
width as necessary. If HO2S voltage remains
excessively low for an extended period of time, DTC
P0131 or P0151 will be set.
DIAGNOSTIC AIDS
Check for the following conditions:
 Heated oxygen sensor wiring – The sensor pigtail
may be routed incorrectly and contacting the exhaus
t
system.
 Poor ECM to engine block grounds.
 Fuel pressure – The system will go lean if pressure is
too low. The ECM can compensate for some
decrease. However, If fuel pressure is too low, a DTC
P0131 or P0151 may be set. Refer to 6E-116 Fue
l
System Diagnosis.

 Lean injector(s) – Perform “Injector Balance Test."
 Exhaust leaks – An exhaust leak may cause outside
air to be pulled into the exhaust gas stream past the
HO2S, causing the system to appear lean. Check fo
r
exhaust leaks that may cause a false lean condition
to be indicated.
 MAF sensor –The system can go lean if the MAF
sensor signal indicates an engine airflo
w
measurement that is not correct. Disconnect the MAF
sensor to see if the lean condition is corrected. If so,
replace the MAF sensor.
 Fuel contamination –Water, even in small amounts,
can be delivered to the fuel injectors. The water can
cause a lean exhaust to be indicated. Excessive
alcohol in the fuel can also cause this condition.
Refer to 6E-116 Fuel System Diagnosisfor the
procedure to check for fuel contamination.
 If none of the above conditions are present, replace
the affected HO2S.

6E-202 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0132 A O2 Sensor Circuit High
Voltage (Bank 1
Sensor 1) 15
P0152 A O2 Sensor Circuit High
Voltage (Bank 2
Sensor 1) 1. No DTC relating to ECT sensor, CMP sensor, CKP sensor,
VSS, injector control circuit, ignition control circuit and O2
sensor circuit no activity (bank 1 & 2).
2. Engine speed is between 1000rpm and 4000rpm.
3. Engine coolant temperature is between 70
and 110
.
4. Vehicle speed is between 0km/h and 120km/h.
5. Engine load is between 80% and 160%.
6. Throttle position fluctuation is below 0.28V.
7. O2 sensor bank 1 or bank 2 output voltage is below
600mV for 50 seconds. "Open Loop" fuel control.

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal high and signal low circuits. The
ECM constantly monitors the HO2S signal during
“closed loop" operation and compensates for a rich o
r
lean condition by decreasing or increasing injector pulse
width as necessary. If the HO2S voltage remains
excessively high for an extended period of time, DTC
P0132 or P0152 will be set.
DIAGNOSTIC AIDS
Check the following items:
 Fuel pressure – The system will go rich if pressure is
too high. The ECM can compensate for some
increase. However, if fuel pressure is too high, a DTC
P0132 or P0152 may be set. Refer to 6E-116 Fue
l
System Diagnosis.
 Perform “Injector Balance Test" – Refer to 6E-116
Fuel System Diagnosis.
 Check the canister for fuel saturation – If full of fuel,
check canister control and hoses.
 MAF sensor –The system can go rich if MAF senso
r
signal indicates an engine airflow measurement that
is not correct. Disconnect the MAF sensor to see it
the rich condition is corrected. If so, replace the MAF
sensor.

 Check for a leak in the fuel pressure regulato
r
diaphragm by checking the vacuum line to the
regulator for the presence of fuel. There should be no
fuel in the vacuum line.

An intermittent throttle position sensor output will
cause the system to go rich due to a false indication
of the engine accelerating.
 Shorted Heated Oxygen Sensor (HO2S) –If the
HO2S is internally shorted, the HO2S voltage
displayed on the Tech 2 will be over 1 volt. Try
disconnecting the affected HO2S with the key “ON,"
engine “OFF." If the displayed HO2S voltage
changes from over 1000 mV to around 450 mV,
replace the HO2S. Silicon contamination of the
HO2S can also cause a high HO2S voltage to be
indicated. This condition is indicated by a powdery
white deposit on the portion of the HO2S exposed to
the exhaust stream. If contamination is noticed,
replace the affected HO2S.
 Open HO2S Signal Circuit or Faulty HO2S–
A poor
connection or open in the HO2S signal circuit can
cause the DTC to set during deceleration fuel mode.
An HO2S which is faulty and not allowing a full
voltage swing between the rich and lean thresholds
can also cause this condition. Operate the vehicle by
monitoring the HO2S voltage with a Tech 2. If the
HO2S voltage is limited within a range between 300
mV to 600 mV, check the HO2S signal circuit wiring
and associated terminal conditions.
 If none of the above conditions are present, replace
the affected HO2S.