fuel pressure ISUZU TF SERIES 2004 Workshop Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–115
P0122 A Throttle Position Sensor Low Input TPS output voltage is below 0.14V. The ECM uses 0% condition as
substitute.TPS output voltage is more than 0.14V. 1. Sensor power supply circuit open or short
to ground circuit.
2. Sensor signal circuit open or short to
ground circuit.
3. Poor connector connection.
4. TPS malfunction.
5. ECM malfunction.J1-7/
J1-15/
P0123 A Throttle Position Sensor High Input TPS output voltage is more than 4.9V. TPS output voltage is below 4.9V. 1. Sensor power supply circuit short to
voltage circuit.
2. Sensor signal circuit short to voltage
circuit.
3. Sensor ground circuit open or short to
voltage circuit.
4. Poor connector connection.
5. TPS malfunction.
6. ECM malfunction.J1-7/
J1-15/
J1-32
P0131 A O
2 Sensor Circuit Low Voltage (Bank 1
Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. O
2 sensor bank 1 output voltage is below
50mV in “Closed Loop” condition. “Open Loop” fuel control. O
2 sensor bank 1 output voltage is more
than 50mV.1. Sensor harness short to ground circuit.
2. O
2 sensor malfunction.
3. ECM malfunction.J2-6/
J2-21
P0132 A O
2 Sensor Circuit High Voltage (Bank 1
Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. O
2 sensor bank 1 output voltage is more
than 952mV in “Closed Loop” condition. O
2 sensor bank 1 output voltage is below
952mV.1. Sensor harness short to voltage circuit.
2. O
2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. IAC valve malfunction.
6. Incorrect fuel pressure.
7. Injector malfunction.
8. ECM malfunction.J2-6/
J2-21
P0134 A O
2 Sensor Circuit No Activity Detected
(Bank 1 Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. Engine run time is longer than 40
seconds.
4. Mass air flow is more than 7g/s.
5. O
2 sensor bank 1 output voltage is
between 300mV and 600mV.O
2 sensor bank 1 output voltage is below
3 0 0 m V c o n s e c u t i v e l y .
O R
O2 sensor bank 1 output voltage is more
than 600mV consecutively.1. Sensor harness open circuit.
2. O
2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. IAC valve malfunction.
6. Incorrect fuel pressure.
7. Injector malfunction.
8. ECM malfunction.J2-6/
J2-21 Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM
Pin No.

6E–118 ENGINE DRIVEABILITY AND EMISSIONSP1167 D Fuel Supply System Rich During
Deceleration Fuel Cutoff1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. O
2 sensor bank 1 output voltage is more
than 550mV in deceleration fuel cutoff
mode.No fail-safe function. O
2 sensor output voltage is below 550mV. 1. Sensor harness open or short to ground
circuit.
2. O
2 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. EVAP purge solenoid valve malfunction.
9. Ignition system malfunction.
10. Spark plug malfunction.
11. ECM malfunction.J2-6/
J2-21
P1171 D Fuel Supply System Lean During Power
Enrichment 1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60deg. C.
3. Mass air flow is below 13.5m/s.
4. O
2 sensor bank 1 output voltage is below
350mV in power enrichment mode. No fail-safe function. O
2 sensor output voltage is more than
350mV.1. Sensor harness open or short to ground
circuit.
2. O
2 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.J2-6/
J2-21
P1625 B ECM System Reset ECM reset has occurred other than “On”. Engine control disabled. Memory are is OK. 1. Electrical interference.
2. Magnetic interference.
3. ECM malfunction.-
P1626 - Immobilizer No Signal No response from immobilizer control unit. 1. Engine does not start.
2. Check engine lamp flash.No recovery. 1. ECM and immobilizer control unit
communication circuit open circuit, short to
ground circuit or short to voltage circuit.
2. ECM malfunction.
3. Immobilizer control unit malfunction.
4. Transponder key malfunction.J2-23/
J2-32
P1631 - Immobilizer Wrong Signal Received response is not correct.1. ECM malfunction.
2. Immobilizer control unit malfunction.
3. Transponder key malfunction.-
P1648 - Wrong Security Code Entered Received incorrect security code.1. ECM malfunction.
2. Immobilizer control unit malfunction.
3. Transponder key malfunction.-
P1649 - Immobilizer Function Not Programmed Immobilizer function is not programmed in the
ECM.ECM malfunction. -
P1693 B Tachometer Output Low Voltage Tacho output circuit short to ground circuit. No fail-safe function. Tacho output circuit is correct condition. 1. Tacho output circuit short to ground circuit.
2. Poor connector connection.
3. ECM malfunction.J2-25 Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM
Pin No.

6E–152 ENGINE DRIVEABILITY AND EMISSIONS
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
Diagnostic Trouble Code P0131 may be set. Refer to
Fuel System Diagnosis.
Lean injector(s) - Perform “I njector Balance Test.”
Vacuum leaks - Check for disconnected or damaged
vacuum hoses and for vacuum leaks at the intake
manifold, throttle body, EGR system, and PCV
system.Ex haust leaks - An ex haust leak may cause outside
air to be pulled into the ex haust gas stream past the
HO2S, causing the system to appear lean. Check for
exhaust leaks that may cause a false lean condition
to be indicated.
Fuel contamination - Water, even in small amounts,
can be delivered to the fuel injectors. The water can
cause a lean ex haust to be indicated. Ex cessive
alcohol in the fuel can also cause this condition. For
the procedure to check for fuel contamination, Refer
to Fuel System Diagnosis.
Diagnostic Trouble Code (DTC) P0131
O
2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
Step A ction 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P0131 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P0131 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 O
2 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 Using the DVM and check the O
2 sensor circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for short to heater ground or
ground circuit.
Was the DVM indicated specified value?
Approximatly
450mV Go to Step 7Go to Step 6
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6E–154 ENGINE DRIVEABILITY AND EMISSIONS
9 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Manifold Absolute Pressure” in the
data display.
Does the Tech 2 indicate correct “Manifold Absolute
Pressure” in accordance with engine speed or
acceleration? —Go to Step 11Go to Step 10
10 Remove the MAP sensor and check for the following
conditions.
Objects blocking the air cleaner.
Objects blocking the MAP sensor.
Objects blocking the throttle valve.
Vacuum leaking at intake duct.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 1. Using the Tech 2, ignition “On” and engine “On”.
2. Select the “Miscellaneous Test” and perform the
“IAC Control” in the “IAC System”.
3. Operate the Tech 2 in accordance with procedure.
Was the engine speed changed, when the IAC valve
is operating step by step?—Go to Step 13Go to Step 12
12 Check for the following conditions.
Objects blocking the IAC valve.
Objects blocking the throttle valve.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 13
13 Check for injector for the affected bank.
Refer to “Injector Coil Test & Injector Balance Test
Procedure” 6E-98 page.
Was the injector operation correct?
—Go to Step 14Refer to Injector
Coil Test &
Injector
Balance Test
Procedure
14 Check for fuel pressure.
Refer to “Fuel System Diagnosis” 6E-108 page.
Was the fuel pressure correct? —Go to Step 15Refer to Fuel
System
Diagnosis
15 Replace the O
2 sensor.
Was the problem solved?—Verify repair Go to Step 16
16 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 17
17 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.—Veri fy repai r— Step A ction Value(s) Yes No

ENGINE DRIVEABILITY AND EMISSIONS 6E–155
DIAGNOSTIC TROUBLE CODE (DTC) P0132 O2 SENSOR CIRCUIT HIGH
VOLTAGE (BANK 1 SENSOR 1)
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) supplies a bias
voltage of about 450 mV between the heated ox ygen
sensor (HO2S) signal and low circuits. The ox ygen
sensor varies the voltage within a range of about 1000
mV when the ex haust is rich, down through about 10
mV when ex haust is lean. The ECM constantly monitors
the HO2S signal during “Closed Loop” operation and
compensates for a rich or lean condition by decreasing
or increasing injector pulse width as necessary. If theBank 1 HO2S 1 voltage remains ex cessively high for an
ex tended period of time, Diagnostic Trouble Code
P0132 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
Diagnostic Trouble Code P0132 may be set. Refer to
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0132 A O
2 Se nsor Circuit High Volta ge (Ba nk 1
Se nsor 1)1. No DTC re lating to MAP senso r, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. Engine coolant temperature is more than
60 de g. C.
3. O
2 se nsor ba nk 1 output vo lta ge is mo re
than 952mV in “Clo se d Lo op” conditio n. “Ope n Lo op” fuel control.

6E–156 ENGINE DRIVEABILITY AND EMISSIONS
Fuel System Diagnosis.
Perform “Injector Balance Test” - Refer to Fuel
System Diagnosis.
Check the EVAP canister for fuel saturation - If full of
fuel, check canister control and hoses. Refer to
Evaporative (EVAP) Emission Control System.
Check for a leak in the fuel pressure regulator
diaphragm by checking the vacuum line to the
regulator for the presence of fuel.An intermittent TPS output will cause the system to
go rich due to a false indication of the engine
accelerating.
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 ex posed to the ex haust stream. If
contamination is noticed, replace the affected HO2S.
Diagnostic Trouble Code (DTC) P0132
O
2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
Step A ction 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P0132 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P0132 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 O
2 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 Using the DVM and check the O
2 sensor circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the the O
2 sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Approximatly
450mV Go to Step 7Go to Step 6
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6E–158 ENGINE DRIVEABILITY AND EMISSIONS
12 Check for the following conditions.
Objects blocking the IAC valve.
Objects blocking the throttle valve.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 13
13 Check for injector for the affected bank.
Refer to “Injector Coil Test & Injector Balance Test
Procedure” 6E-98 page.
Was the injector operation correct?
—Go to Step 14Refer to Injector
Coil Test &
Injector
Balance Test
Procedure
14 Check for fuel pressure.
Refer to “Fuel System Diagnosis” 6E-108 page.
Was the fuel pressure correct? —Go to Step 15Refer to Fuel
System
Diagnosis
15 Replace the O
2 sensor.
Was the problem solved?—Verify repair Go to Step 16
16 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 17
17 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.—Veri fy repai r— Step A ction Value(S) Yes No

6E–162 ENGINE DRIVEABILITY AND EMISSIONS
10 Check for the following conditions.
Objects blocking the IAC valve.
Objects blocking the throttle valve.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 Check for injector for the affected bank.
Refer to “Injector Coil Test & Injector Balance Test
Procedure” 6E-98 page.
Was the injector operation correct?
—Go to Step 12Refer to Injector
Coil Test &
Injector
Balance Test
Procedure
12 Check for fuel pressure.
Refer to “Fuel System Diagnosis” 6E-108 page.
Was the fuel pressure correct? —Go to Step 13Refer to Fuel
System
Diagnosis
13 Replace the O
2 sensor.
Was the problem solved?—Verify repair Go to Step 14
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.—Veri fy repai r— Step A ction Value(s) Yes No

ENGINE DRIVEABILITY AND EMISSIONS 6E–211
DIAGNOSTIC TROUBLE CODE (DTC) P1167 FUEL SUPPLY SYSTEM RICH
DURING DECELERATION FUEL CUT OFF
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during deceleration (fuel cut
off). The ECM monitors the voltage of the ox ygen
sensor during fuel cut off. When a fuel cut off mode of
operation is requested during “Closed Loop” operation
(by deceleration), the ECM will provide more fuel to the
engine. Under these conditions the ECM should detect
a “lean” condition (low ox ygen sensor voltage). If this“lean” ex haust is not detected at this time, a Diagnostic
Trouble Code P1167 will 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
Diagnostic Trouble Code P1167 may be set. Refer to
Fuel System Diagnosis.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1167 D Fuel Supply Sy stem Rich During
De ce le ration Fue l Cuto ff1. No DTC re lating to MAP senso r, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. O
2 se nsor ba nk 1 output vo lta ge is mo re
than 550mV in deceleration fuel cutoff
mo de .No fail-safe function.

6E–212 ENGINE DRIVEABILITY AND EMISSIONS
Perform “I njector Balance Test” - Refer to Fuel
System Diagnosis.
Check the EVAP canister for fuel saturation - If full of
fuel, check canister control and hoses. Refer to
Evaporative (EVAP) Emission Control System.
Check for a leak in the fuel pressure regulator
diaphragm by checking the vacuum line to toe
regulator for the presence of fuel.An intermittent TP sensor output will cause the
system to go rich due to a false indication of the
engine accelerating.
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 ex posed to the ex haust stream. If
contamination is noticed, replace the affected HO2S.
Diagnostic Trouble Code (DTC) P1167
Fuel Supply Sy stem Rich During Deceleration Fuel Cutoff
Step A ction 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1167 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1167 stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 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” in
accordance with accelerator pedal operation? —Go to Step 6Go to Step 5
5 Check for the following conditions.
Objects blocking the throttle valve.
Incorrectly installed.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 12
6 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Manifold Absolute Pressure” in the
data display.
Does the Tech 2 indicate correct “Manifold Absolute
Pressure” in accordance with engine speed or
acceleration? —Go to Step 8Go to Step 7
7 Remove the MAP sensor and check for the following
conditions.
Objects blocking the air cleaner.
Objects blocking the MAP sensor.
Objects blocking the throttle valve.
Vacuum leaking at intake duct.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 13