check engine ISUZU TF SERIES 2004 Workshop Manual

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

6E–164 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM - Inspect harness
connectors for backed-out terminals, improper
mating, broken locks, improperly formed or damagedterminals, and poor terminal-to-wire connection.
Damaged harness - Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive
and open circuits.
Diagnostic Trouble Code (DTC) P0135
O
2 Sensor Heater Circuit (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 P0135 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 P0135 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 Visually check the O
2 sensor.
Was the problem found? —Go to Step 11Go to Step 6
6 Using the DVM and check the O
2 sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect O
2 sensor connector
3. Measure the resistance of heater.
Was the tester indicated specified value?
Approx imately
12.5
at 20°CGo to Step 7Go to Step 11
3431
C56(J2) E77
3 4
1234
O2 Sensor

ENGINE DRIVEABILITY AND EMISSIONS 6E–165
7 Using the DVM and check the heater power supply
circuit for the affected cylinder.
1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 9Go to Step 8
8 Repair the open or short to ground circuit between the
“O
2 Sensor” fuse (10A) and O2 sensor.
Is the action complete?—Veri fy repai r—
9 Using the DVM and check the heater ground circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the O
2 sensor connector.
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the O
2 sensor connector and ECM
connector.
3. Check the circuit for open or short to ground
circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 10 Step A ction Value(s) Yes No
4
V
E77
J2-31Breaker BoxE-77





331E56(J2) E77

6E–166 ENGINE DRIVEABILITY AND EMISSIONS
10 Using the DVM and check the heater ground circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for short to voltage circuit.
Was the DVM indicated voltage?
—Repair faulty
harness and
verify repair Go to Step 12
11 Replace the O
2 sensor.
Was the problem solved?—Verify repair Go to Step 12
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
13 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
3
V
E77

6E–168 ENGINE DRIVEABILITY AND EMISSIONS
Trouble Code is set. This Diagnostic Trouble Code is
also set if an injector driver is shorted to voltage.
Diagnostic Aids
An injector driver circuit that is open or shorted to
voltage will cause a Diagnostic Trouble Code P0201 to
set. It will also cause a misfire due to an inoperativeinjector. A misfire Diagnostic Trouble Code will also be
set indicating which cylinder is inoperative.
Long term and short term fuel trims that are ex cessively
high or low are a good indication that an injector is
faulty.
Use Fuel Injector Coil Test Procedure to check for faulty
injectors.
Diagnostic Trouble Code (DTC) P0201 Injector 1 Control Circuit
Diagnostic Trouble Code (DTC) P0202 Injector 2 Control Circuit
Diagnostic Trouble Code (DTC) P0203 Injector 3 Control Circuit
Diagnostic Trouble Code (DTC) P0204 Injector 4 Control Circuit
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 P0201, P0202, P0203 or P0204 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 P0201, P0202, P0203 or P0204 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 injector 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 injector for the affected cylinder.
Was the problem found? —Go to Step 11Go to Step 6
22
89 11
E-60(J1)
E-6/E-7/E-8/E-9

ENGINE DRIVEABILITY AND EMISSIONS 6E–169
6 Using the DVM and check the injector coil for the
affected cylinder.
1. Ignition “Off”, engine “Off”.
2. Disconnect injector connector for the affected
cylinder.
3. Measure the resistance of injector coil.
Was the tester indicated specified value?
Approx imately
12.5
at 20°CGo to Step 7Go to Step 11 Step A ction Value(s) Yes No
Injecto r





6E–170 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the injector power supply
circuit for the affected cylinder.
1. Ignition “On”, engine “Off”.
2. Disconnect the injector connector for the affected
cylinder.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 9Go to Step 8
8 Repair the open or short to ground circuit between the
“IGN” fuse (15A) and injector for the affected cylinder.
Is the action complete?—Veri fy repai r— Step A ction Value(s) Yes No
V
1
E-6 No.1 Cylinder
V
1
E-7 No.2 Cylinder
V
1
E-8 No.3 Cylinder
V
1
E-9 No.4 Cylinder

ENGINE DRIVEABILITY AND EMISSIONS 6E–171
9 Using the DVM and check the injector signal circuit for
the affected cylinder.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the injector connector for the affected
cylinder.
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 10 Step A ction Value(s) Yes No
J1-9Breaker Box




No. 1 Cyli nder
E-6
J1-22Breaker Box




No. 2 Cylinder
E-7
J1-8Breaker Box



No. 3 Cy linder
E-8

J1-11Breaker Box




No. 4 Cylinder
E-9

6E–172 ENGINE DRIVEABILITY AND EMISSIONS
9Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the injector connector for the affected
cylinder and ECM connector.
3. Check the circuit for open or short to ground
circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 10 Step A ction Value(s) Yes No
E-60(J1)
E-6
9
2
No.1 Cylinder
E-60(J1)
E-7
22
2
No.2 Cylinder
E-60(J1)
E-8
8
2
No.3 Cylinder
E-60(J1)
E-9
11
2
No.4 Cylinder

ENGINE DRIVEABILITY AND EMISSIONS 6E–173
10 Using the DVM and check the injector signal circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the injector connector for the affected
cylinder.
3. Check the circuit for short to voltage circuit.
Was the DVM indicated voltage?
—Repair faulty
harness and
verify repair Go to Step 12
11 Replace the injector for the affected cylinder.
Was the problem solved?—Verify repair Go to Step 12
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
13 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
V
2
E-6 No.1 Cylinder
V
2
E-7 No.2 Cylinder
V
2
E-8 No.3 Cylinder
V
2
E-9 No.4 Cylinder