sensor ISUZU TROOPER 1998 Service Repair Manual

6E±58
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0108 (Flash DTC 34)
MAP Sensor Circuit High Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively high, DTC P0108
will be set.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0108 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:

Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.

Poor connection at ECM ± 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
MAP display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
If DTC P0108 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently.

6E±59 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
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
2Put the engine into an idling status.
Is the MAP voltage value displayed on the Tech 2
above the specified value?
4 VGo to Step 3Go to Step 4
31. Turn off the ignition switch.
2. Remove the sensor connector connection.
3. Turn on the ignition switch ªONº.
Is the MAP voltage value displayed on the Tech 2 below
the specified value?
1 VGo to Step 5Go to Step 6
4Is the MAP voltage value displayed on the Tech 2 below
the specified value?
1 V
Refer to
Chart P0107
Refer to
Diagnostic
Aids
and
Symptom
Diagnosis
5Connect the relay and solenoid checker
(5-8840-0386-0) to the battery voltage, then check the
sensor grounding circuit.
Does the checker lamp come on?
ÐGo to Step 7Go to Step 8
6A voltage short circuit occurs in the MAP signal circuit
or this circuit is shorted with the 5V power circuit.
Repair the harness or Replace the ECM (Refer to the
Data Programming in Case of ECM change).
Is the action complete?
ÐVerify repairÐ
7Replace the MAP sensor hose or the MAP sensor.
Is the action complete?
ÐVerify repairÐ
8Repair the harness for open ground circuit.
Is the action complete?
ÐVerify repairÐ

6E±60
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0112 (Flash DTC 23)
IAT Sensor Circuit Low Voltage
060RW129
Circuit Description
The Intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module ECM applies 5 volts
through a pull-up resistor to the IAT sensor. When the
intake air is cold, the sensor resistance is high and the
ECM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower, causing the ECM to monitor a lower voltage. DTC
P0112 will set when the ECM detects an excessively low
signal voltage on the Intake air temperature sensor signal
circuit.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0112 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
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 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
IAT display on the Tech 2 while moving connectors and
wiring harnesses related to the IAT sensor. A change
in the IAT display will indicate the location of the fault.
If DTC P0112 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±61 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 P0112 can be repeated only by duplicating
the Failure Records condition, refer to the
Temperature vs. Resistance Value table. The table
may be used to test the IAT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº sensor that may be stored above or below
a certain temperature. If this is the case, replace
the IAT sensor. If the IAT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Intake Air Temperature Sensor

C
FOhms
Temperature vs. Resistance Values
(approximate)
25772796
15594450
5417280
DTC P0112 ± IAT 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. Using a Tech 2, monitor the intake air temperature
(IAT).
Is the intake air temperature greater than the specified
value?
148
C
(283
F)
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the ª DTCº info for DTC
P0112.
Does the Tech 2 indicate DTC P0112 failed this
ignition?
Ð
Refer to Test
Description
Refer to
Diagnostic
Aids
41. Ignition ªOFF.º
2. Disconnect the IAT sensor electrical connector.
3. Ignition ªON.º
4. Observe the manifold air temperature on the Tech 2.
Is the manifold air temperature below the specified
value?
±38
C
(±36
F)
Go to Step 6Go to Step 5
51. Ignition ªOFF.º
2. Disconnect the ECM electrical connectors.
3. Check the IAT sensor signal circuit for a short to
ground.
Is the IAT sensor signal circuit shorted to ground?
ÐVerify repairGo to Step 7
6Replace the IAT 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±62
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0113 (Flash DTC 23)
IAT Sensor Circuit High Voltage
060RW129
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module ECM applies 5 volts
through a pull-up resistor to the IAT sensor. When the
intake air is cold, the sensor resistance is high and the
ECM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower causing the ECM to monitor a lower voltage. DTC
P0113 will set when the ECM detects an excessively high
signal voltage on the intake air temperature sensor signal
circuit.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0113 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
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 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
IAT display on the Tech 2 while moving connectors and
wiring harnesses related to the IAT sensor. A change
in the IAT display will indicate the location of the fault.
If DTC P0113 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±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±64
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0113 ±IAT Sensor Circuit High Voltage

 
StepNo Ye s Value(s) Action
81. Ignition ªOFF.º
2. Disconnect the ECM, and check the IAT signal
circuit for an open.
3. If the IAT sensor signal circuit is open, repair it as
necessary.
Was the IAT signal circuit open?
ÐVerify repairGo to Step 9
9Check for a poor sensor ground or IAT 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 IAT 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±65 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0117 (Flash DTC 14)
ECT Sensor Low Voltage
060RW129
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted on a coolant crossover pipe at the
rear of the engine. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine coolant is cold,
the sensor (thermistor) resistance is high, therefore the
ECM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes lower,
and the ECT signal voltage measured at the ECM drops.
Action Taken When the DTC Sets

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0117 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at ECM ± Inspect harness connectors
for backed-out terminals, improper mating, brokenlocks, 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
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the ECT sensor. A
change in the ECT display will indicate the location of
the fault.
If DTC P0117 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently.
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 P0117 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 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.

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±67 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0118 (Flash DTC 14)
ECT Sensor High Voltage
060RW129
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in on a coolant crossover pipe at the
rear of the engine. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine coolant is cold,
the sensor (thermistor) resistance is high, therefore the
ECM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes less, and
the ECT signal voltage measured at the ECM drops.
Action Taken When the DTC Sets

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0118 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
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 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
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the ECT sensor. A
change in the ECT display will indicate the location of
the fault.
If DTC P0118 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.