electrical system ISUZU TROOPER 1998 Service Repair Manual

6E±63 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Verifies that the fault is present.
3. If DTC P0113 can be repeated only by duplicating
the Failure Records conditions, refer to the
ªTemperature vs. Resistance Valuesº table. The
table may be used to test the MAT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº sensor that may be open above or below a
certain temperature. If this is the case, replace the
MAT sensor. If the MAT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Manifold Air Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
25772796
15594450
5417280
DTC P0113 ±IAT Sensor Circuit High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Ignition ªON,º engine ªOFF.º Observe the ªIntake Air
Tempº display on the Tech 2.
Is the ªIntake Air Tempº below the specified value?
±38
C
(±36
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data
parameters.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ª DTCº info for DTC P0113.
Does the Tech 2 indicate DTC P0113 failed?
Ð
Refer to Test
Description
Refer to
Diagnostic
Aids
41. Ignition ªOFF.º
2. Disconnect the IAT sensor electrical connector.
3. Jumper the IAT signal circuit and the sensor ground
circuit together at the IAT sensor harness
connector.
4. Ignition ªON.º
5. Observe the ªIntake Air Tempº display on the Tech
2.
Is the ªIntake Air Tempº at the specified value?
140
C
(284
F)
Go to Step 6Go to Step 5
51. Jumper the IAT signal circuit at the IAT sensor
harness connector to chassis ground.
2. Observe the ªIntake Air Tempº display on the Tech
2.
Is the ªIntake Air Tempº at the specified value?
140
C
(284
F)
Go to Step 7Go to Step 8
6Check for poor connections at the IAT sensor and
replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 10
71. Ignition ªOFF.º
2. Disconnect the ECM, and check the IAT sensor
ground circuit for an open.
3. If the IAT sensor ground circuit is open, repair it as
necessary.
Was the IAT sensor ground circuit open?
ÐVerify repairGo to Step 9

6E±66
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Engine Coolant Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
25772796
15594450
DTC P0117 ± ECT Sensor Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªEng Cool Tempº display on the Tech 2.
Is the ªEng Cool Tempº below the specified value?
139
C
(282
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ª DTCº info for DTC P0117.
Does the Tech 2 indicate DTC P0117 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Disconnect the ECT sensor electrical connector.
2. Observe the ªEng Cool Tempº display on the Tech 2.
Is the ªEng Cool Tempº at the specified value?
±39
C
(±38
F)
Go to Step 6Go to Step 5
51. Ignition ªOFF.º
2. Disconnect the ECM and check the ECT signal
circuit for a short to ground or a short to the sensor
ground circuit.
3. If the ECT signal circuit is shorted. repair it as
necessary.
Was the ECT signal circuit shorted to ground?
ÐVerify repairGo to Step 7
6Replace the ECT sensor.
Is the action complete?
ÐVerify repairÐ
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±68
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
3. If DTC P0118 can be repeated only by duplicating
the Failure Records conditions, refer to the
ªTemperature vs. Resistance Valueº table. The
table may be used to test the ECT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the ECT sensor. If the ECT sensor appears to be
OK, the fault is intermittent; refer to
Diagnostic Aids.
Engine Coolant Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
80176332
25772796
15594450
DTC P0118 ± ECT Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªEng Cool Tempº display on the Tech 2.
Is the ªEng Cool Tempº below the specified value?
±39
C
(±38
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor the ª DTCº info for DTC
P0118.
Does the Tech 2 indicate DTC P0118 failed?
Ð
Refer to Test
Description
Refer to
Diagnostic
Aids
41. Disconnect the ECT sensor electrical connector.
2. Jumper the ECT signal circuit and the sensor
ground circuit together at the ECT sensor harness
connector.
3. Observe the ªEng Cool Tempº display on the Tech 2.
Is the ªEng Cool Tempº at the specified value?
140
C
(284
F)
Go to Step 6Go to Step 5
51. Jumper the ECT signal circuit at the ECT sensor
harness connector to chassis ground.
2. Observe the ªEng Cool Tempº display on the Tech 2.
Is the ªEng Cool Tempº at the specified value?
140
C
(284
F)
Go to Step 7Go to Step 8
6Check for poor connections at the ECT sensor and
replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 10
71. Ignition ªOFF.º
2. Disconnect the ECM, and check the ECT sensor
ground circuit for an open.
3. If the ECT sensor ground circuit is open, repair it as
necessary.
Was the ECT sensor ground circuit open?
ÐVerify repairGo to Step 9

6E±76
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0123 ± AP Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Check the AP sensor signal circuit.
Was the AP sensor signal circuit open or darmage?
Ð
Replace the
APS circuit
Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. With the throttle closed, observe the ªAP Sensorº
display on the Tech 2.
Is the ªAP Sensorº above the specified value?
4.5 VGo to Step 5Go to Step 4
41. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0123.
Does the Tech 2 indicate DTC P0123 failed.
ÐGo to Step 5
Refer to
Diagnostic
Aids
51. Disconnect the AP sensor electrical connector.
2. Observe the ªAP Sensorº display on the Tech 2.
Is the ªAP Sensorº near the specified value?
0 VGo to Step 6Go to Step 7
6Probe the sensor ground circuit at the AP sensor
harness connector with a test light connected to B+.
Is the test light ªON?º
ÐGo to Step 8Go to Step 11
71. Ignition ªOFF,º disconnect the ECM.
2. Ignition ªON,º engine ªOFF.º
3. Check for a short to voltage on the AP sensor signal
circuit.
4. If the AP sensor signal circuit is shorted, repair it as
necessary.
Was the AP sensor signal circuit shorted?
ÐVerify repairGo to Step 13
81. Ignition ªON.º
2. Monitor the ªAP Sensorº Tech 2 display while
disconnecting each of the components that share
the 5 volt reference ªJ2º circuit (one at a time).
3. If the ªAP Sensorº Tech 2 display changes, replace
the component that caused the display to change
when disconnected.
Does disconnecting any of these components cause
the ªAP Sensorº display to change?
ÐVerify repairGo to Step 9
91. Ignition ªOFF,º disconnect the ECM.
2. Ignition ªON,º engine ªOFF.º
3. Check for a short to B+ on the 5 volt reference ªAº
circuit.
4. If the 5 volt reference ªJ2º circuit is shorted, repair it
as necessary.
Was the 5 volt reference ªJ2º circuit shorted?
ÐVerify repairGo to Step 10
10Check for poor electrical connections at the AP sensor
and replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 12

6E±79 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0182 ± FT Sensor Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªFuel Tempº display on the Tech 2.
Is the ªFuel Tempº below the specified value?
139
C
(282
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ª DTCº info for DTC P0182.
Does the Tech 2 indicate DTC P0182 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Disconnect the FT sensor electrical connector.
2. Observe the ªFuel Tempº display on the Tech 2.
Is the ªFuel Tempº at the specified value?
±39
C
(±38
F)
Go to Step 6Go to Step 5
51. Ignition ªOFF.º
2. Disconnect the ECM and check the FT signal circuit
for a short to ground or a short to the sensor ground
circuit.
3. If the FT signal circuit is shorted. repair it as
necessary.
Was the FT signal circuit shorted to ground?
ÐVerify repairGo to Step 7
6Replace the FT sensor.
Is the action complete?
ÐVerify repairÐ
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±81 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0183 ± FT Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªFuel Tempº display on the Tech 2.
Is the ªFuel Tempº below the specified value?
±39
C
(±38
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor the ª DTCº info for DTC
P0183.
Does the Tech 2 indicate DTC P0183 failed?
Ð
Refer to Test
Description
Refer to
Diagnostic
Aids
41. Disconnect the FT sensor electrical connector.
2. Jumper the FT signal circuit and the sensor ground
circuit together at the FT sensor harness connector.
3. Observe the ªFuel Tempº display on the Tech 2.
Is the ªFuel Tempº at the specified value?
140
C
(284
F)
Go to Step 6Go to Step 5
51. Jumper the FT signal circuit at the FT sensor
harness connector to chassis ground.
2. Observe the ªFuel Tempº display on the Tech 2.
Is the ªFuel Tempº at the specified value?
140
C
(284
F)
Go to Step 7Go to Step 8
6Check for poor connections at the FT sensor and
replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 10
71. Ignition ªOFF.º
2. Disconnect the ECM, and check the FT sensor
ground circuit for an open.
3. If the FT sensor ground circuit is open, repair it as
necessary.
Was the FT sensor ground circuit open?
ÐVerify repairGo to Step 9
81. Ignition ªOFF.º
2. Disconnect the ECM, and check the FT signal
circuit for an open.
3. If the FT sensor signal circuit is open, repair it as
necessary.
Was the FT signal circuit open?
ÐVerify repairGo to Step 9
9Check for a poor sensor ground or FT signal circuit
terminal connection at the ECM and replace
terminal(s) if necessary.
Did any of the terminals need to be replaced?
ÐVerify repairGo to Step 11
10Replace the FT sensor.
Is the action complete?
ÐVerify repairÐ
11Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±85 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0193 ± RP Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ª DTCº info for DTC P0108.
Does the Tech 2 indicate DTC P0108 failed this
ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Check the RP sensor signal circuit.
Was the RP sensor signal circuit open or darmage?
Ð
Replace the
RP circuit
Go to Step 4
4Probe the sensor ground circuit with a test light to B+.
Is the test light ªON?º
ÐGo to Step 5Go to Step 7
51. Check the RP signal circuit for a short to voltage or a
short to the 5 volt reference ªJ1º circuit.
2. If the RP sensor signal circuit is shorted, repair
circuit as necessary.
Was the RP sensor signal circuit shorted?
ÐVerify repairGo to Step 6
61. Check for a poor sensor ground terminal connection
at the RP sensor electrical connector.
2. If a problem if found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 7
71. Check for a poor sensor ground terminal connection
at the ECM.
2. If a problem is found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 8
81. Check the continuity of the RP sensor ground
circuit.
2. If the RP sensor ground circuit measures over 5
ohms, repair open or poor connection.
Was a condition found and corrected?
ÐVerify repairGo to Step 9
9Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify RepairÐ

6E±95 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
3. If DTC P0197 can be repeated only by duplicating
the Failure Records conditions, refer to the
ªTemperature vs. Resistance Valuesº table. The
table may be used to test the OT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the OT sensor. If the OT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Engine Oil Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
80176332
25772796
15594450
DTC P0197 ± OT Sensor Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªEng Oil Tempº display on the Tech 2.
Is the ªEng Oil Tempº below the specified value?
139
C
(282
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ª DTCº info for DTC P0197.
Does the Tech 2 indicate DTC P0197 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Disconnect the OT sensor electrical connector.
2. Observe the ªEng Oil Tempº display on the Tech 2.
Is the ªEng Oil Tempº at the specified value?
±39
C
(±38
F)
Go to Step 6Go to Step 5
51. Ignition ªOFF.º
2. Disconnect the ECM and check the OT signal circuit
for a short to ground or a short to the sensor ground
circuit.
3. If the OT signal circuit is shorted. repair it as
necessary.
Was the OT signal circuit shorted to ground?
ÐVerify repairGo to Step 7
6Replace the OT sensor.
Is the action complete?
ÐVerify repairÐ
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±97 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
3. If DTC P0198 can be repeated only by duplicating
the Failure Records conditions, refer to the
ªTemperature vs. Resistance Valueº table. The
table may be used to test the OT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the OT sensor. If the OT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Engine Oil Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
80176332
25772796
15594450
DTC P0198 ± OT Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Observe the ªEng Oil Tempº display on the Tech 2.
Is the ªEng Oil Tempº below the specified value?
±39
C
(±38
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor the ª DTCº info for DTC
P0198.
Does the Tech 2 indicate DTC P0198 failed?
Ð
Refer to Test
Description
Refer to
Diagnostic
Aids
41. Disconnect the OT sensor electrical connector.
2. Jumper the OT signal circuit and the sensor ground
circuit together at the OT sensor harness
connector.
3. Observe the ªEng Oil Tempº display on the Tech 2.
Is the ªEng Oil Tempº at the specified value?
140
C
(284
F)
Go to Step 6Go to Step 5
51. Jumper the OT signal circuit at the OT sensor
harness connector to chassis ground.
2. Observe the ªEng Oil Tempº display on the Tech 2.
Is the ªEng Oil Tempº at the specified value?
140
C
(284
F)
Go to Step 7Go to Step 8
6Check for poor connections at the OT sensor and
replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 10
71. Ignition ªOFF.º
2. Disconnect the ECM, and check the OT sensor
ground circuit for an open.
3. If the OT sensor ground circuit is open, repair it as
necessary.
Was the OT sensor ground circuit open?
ÐVerify repairGo to Step 9

6E±147 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1486 ± ITP Sensor High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. With the throttle closed by the hand, observe the
ªITP Sensorº display on the Tech 2.
Is the ªITP Sensorº above the specified value?
4.88 VGo to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P1486.
Does the Tech 2 indicate DTC P1486 failed.
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check for poor electrical connections at the ITP sensor
and replace terminals if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 5
51. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2 monitor the ªDTCº info for DTC
P1486.
Dose the Tech 2 indicate DTC P1486 failed.
ÐGo to Step 6
Refer to
Diagnostic
Aids
6Replace the intake throttle.
Is the action complete?
ÐVerify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ