ISUZU TROOPER 1998 Service Repair Manual

6E±98
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0198 ± OT Sensor High Voltage

 
StepNo Ye s Value(s) Action
81. Ignition ªOFF.º
2. Disconnect the OT, and check the OT signal circuit
for an open.
3. If the OT sensor signal circuit is open, repair it as
necessary.
Was the OT signal circuit open?
ÐVerify repairGo to Step 9
9Check for a poor sensor ground or OT 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 ECT 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±99 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0201 (Flash DTC 51)
Injector # 1 Circuit Fault
060RW134
Circuit Description
The Engine Control Module ECM has four individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the ECM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.
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 P0201 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage
will cause a DTC P0201 to set.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.3. This step determines if DTC P0201 is the result of a
hard failure or an intermittent condition.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1±4.
Tech±2 must be used for this test.
Test Procedure:
1. Connect Tech±2 to the vehicle DLC.
2. Set Ignition Switch to the ªONº position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector (Switch on),
making sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.
6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not
been confirmed, its electric circuit or the injector
proper is faulty.

6E±100
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0201 ± Injector # 1 Circuit Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Will the engine start?
ÐGo to Step 3
Go to Engine
Cranks But
Will Not Run
chart
31. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Does DTC P0201 reset?
ÐGo to Step 5Go to Step 4
41. Review the Freeze Frame data with the ignition
ªONº and the engine ªOFFº and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions as noted.
Does P0201 reset?
ÐGo to Step 5Ð
5Check the Injector test.
Does the working noise confirm?
ÐGo to Step 6Go to Step 7
61. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Dose DTC P0201 reset?
ÐVerify repairGo to Step 7
7Check for an open circuit between the injector
connector and the ECM.
Was there an open circuit?
ÐGo to Step 8Go to Step 9
8Repair the open circuit.
Is the action complete?
ÐVerify repairÐ
9Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairGo to Step 10
10Replace the Injector (Refer to the Injector Group Sign
Programming).
Is the action complete?
ÐVerify repairÐ

6E±101 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0202 (Flash DTC 52)
Injector # 2 Circuit Fault
060RW134
Circuit Description
The Engine Control Module ECM has four individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the ECM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.
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 P0202 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage
will cause a DTC P0202 to set.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.3. This step determines if DTC P0202 is the result of a
hard failure or an intermittent condition.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1±4.
Tech±2 must be used for this test.
Test Procedure:
1. Connect Tech±2 to the vehicle DLC.
2. Set Ignition Switch to the ªONº position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector (Switch on),
making sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.
6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not
been confirmed, its electric circuit or the injector
proper is faulty.

6E±102
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0202 ± Injector # 2 Circuit Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Will the engine start?
ÐGo to Step 3
Go to Engine
Cranks But
Will Not Run
chart
31. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Does DTC P0202 reset?
ÐGo to Step 5Go to Step 4
41. Review the Freeze Frame data with the ignition
ªONº and the engine ªOFFº and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions as noted.
Does P0202 reset?
ÐGo to Step 5Ð
5Check the Injector test.
Does the working noise confirm?
ÐGo to Step 6Go to Step 7
61. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Dose DTC P0202 reset?
ÐVerify repairGo to Step 7
7Check for an open circuit between the injector
connector and the ECM.
Was there an open circuit?
ÐGo to Step 8Go to Step 9
8Repair the open circuit.
Is the action complete?
ÐVerify repairÐ
9Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairGo to Step 10
10Replace the Injector (Refer to the Injector Group Sign
Programming).
Is the action complete?
ÐVerify repairÐ

6E±103 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0203 (Flash DTC 52)
Injector # 3 Circuit Fault
060RW134
Circuit Description
The Engine Control Module ECM has four individual
injector driver circuits. Each controls an injector. When
the driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the ECM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.
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 P0203 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage
will cause a DTC P0203 to set.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.3. This step determines if DTC P0203 is the result of a
hard failure or an intermittent condition.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1±4.
Tech±2 must be used for this test.
Test Procedure:
1. Connect Tech±2 to the vehicle DLC.
2. Set Ignition Switch to the ªONº position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector (Switch on),
making sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.
6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not
been confirmed, its electric circuit or the injector
proper is faulty.

6E±104
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0203 ± Injector # 3 Circuit Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Will the engine start?
ÐGo to Step 3
Go to Engine
Cranks But
Will Not Run
chart
31. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Does DTC P0203 reset?
ÐGo to Step 5Go to Step 4
41. Review the Freeze Frame data with the ignition
ªONº and the engine ªOFFº and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions as noted.
Does P0203 reset?
ÐGo to Step 5Ð
5Check the Injector test.
Does the working noise confirm?
ÐGo to Step 6Go to Step 7
61. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Dose DTC P0203 reset?
ÐVerify repairGo to Step 7
7Check for an open circuit between the injector
connector and the ECM.
Was there an open circuit?
ÐGo to Step 8Go to Step 9
8Repair the open circuit.
Is the action complete?
ÐVerify repairÐ
9Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairGo to Step 10
10Replace the Injector (Refer to the Injector Group Sign
Programming).
Is the action complete?
ÐVerify repairÐ

6E±105 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0204 (Flash DTC 54)
Injector # 4 Circuit Fault
060RW134
Circuit Description
The Engine Control Module ECM has four individual
injector driver circuits. Each controls an injector. When
the driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the ECM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.
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 P0204 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage
will cause a DTC P0204 to set.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.3. This step determines if DTC P0204 is the result of a
hard failure or an intermittent condition.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1±4.
Tech±2 must be used for this test.
Test Procedure:
1. Connect Tech±2 to the vehicle DLC.
2. Set Ignition Switch to the ªONº position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector (Switch on),
making sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.
6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not
been confirmed, its electric circuit or the injector
proper is faulty.

6E±106
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0204 ± Injector #4 Circuit Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Will the engine start?
ÐGo to Step 3
Go to Engine
Cranks But
Will Not Run
chart
31. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Does DTC P0204 reset?
ÐGo to Step 5Go to Step 4
41. Review the Freeze Frame data with the ignition
ªONº and the engine ªOFFº and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions as noted.
Does P0204 reset?
ÐGo to Step 5Ð
5Check the Injector test.
Does the working noise confirm?
ÐGo to Step 6Go to Step 7
61. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.
Dose DTC P0204 reset?
ÐVerify repairGo to Step 7
7Check for an open circuit between the injector
connector and the ECM.
Was there an open circuit?
ÐGo to Step 8Go to Step 9
8Repair the open circuit.
Is the action complete?
ÐVerify repairÐ
9Is the action complete?ÐVerify repairGo to Step 10
10Replace the Injector (Refer to the Injector Group Sign
Programming).
Is the action complete?
ÐVerify repairÐ

6E±107 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0217 (Flash DTC 22)
High Coolant Temp Waring
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 P0217 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 P0217 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.