check engine ISUZU TROOPER 1998 Service Repair Manual

6E±165 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0601 (Flash DTC 55)
ECM Checksum Error
Action Taken When the DTC Sets

The ECM will not illuminate the malfunction indicator
lamp (MIL).

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

DTC P0601 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids

DTC P0601 indicates that the contents of the
EEPROM have changed since the ECM was
programmed. The only possible repair is ECM
replacement. Remember to program the replacement
ECM with the correct software and calibration for the
vehicle.
DTC P0601 ± ECM Checksum Error

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±166
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0650 (Flash DTC 77)
Check Engine Lamp Circuit Open/Short
060RW136
Circuit Description
The check engine lamp circuit receives through Meter
10A fuse the battery, current flowing in the order of Meter
and check engine lamp.
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 P0650 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
lamp test display on the Tech 2 while moving
connectors and wiring harnesses related to the check
engine lamp. A change in the display will indicate the
location of the fault.
If the Tech 2 indicate DTCs P0650 and P0381, check the
meter circuit necessarily.

6E±167 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0650 ± Check Engine Lamp Open/Short

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 ªLamp Testº display on the Tech 2.
Is the ªLamp Testº operating?
Ð
Refer to
Diagnostic
Aids
Go 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 ªDTCº info for DTC
P0650.
5. If the Tech 2 indicate DTCs P0650 and P0381,
check the meter circuit necessarily.
Does the Tech 2 indicate DTC P0650 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check the Check Engine Lamp circuit for a poor
connection at the Meter and replace the bulb if
necessary.
Did the bulb require replacement?
ÐVerify repairGo to Step 5
5Using the Tech 2.
Does the Tech 2 indicate DTC P0650 failed?
ÐGo to Step 6Ð
6Check the Meter circuit for a poor connection.
Did the Meter require repair?
ÐVerify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±168
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0654 (Flash DTC 27)
Tachometer Circuit Open/Short
060RW136
Circuit Description
The Tach Meter circuit receives through Meter 10A fuse
from the battery, current flowing in the order of Mater and
the Tach Meter.
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 P0650 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 Tech 2 indicat DTCs 0654, P0650 and P0381,
Check the meter circuit necessarily.

6E±169 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0654 ± Tachometer Circuit Open/Short

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 the ªDTCº info for DTC
P654.
Does the Tech 2 indicate DTC P0654 failed?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Check the Tach meter circuit for a poor connection at
the Meter and replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 4
4Using the Tech 2.
Does the Tech 2 indicate DTC P0654 failed?
ÐVerify repairGo to Step 5
5Check the Tach Meter circuit for a poor connection.
Did the terminal require replacement?
ÐVerify repairGo to Step 6
6Replace the tachometer.
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

6E±170
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1655 (Flash DTC 17)
Thermo Relay Circuit Open/Short
060RW130
Circuit Description
The thermo relay circuit receives current through air con
10A fuse from the battery, current flowing in the order of
the thermo relay and thermo SW.
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 P1655 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.

6E±171 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1655 ± Thermo Relay Circuit Open/Short

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 ªBatteri Voltageº display on the Tech 2.
Is the ªBatteri Voltageº below the specified value?
11 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 the ªSpecific DTCº info for
DTC P1655.
Does the Tech 2 indicate DTC P1655 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check the Thermo Relay circuit for a poor connection
and replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 5
5Check the Thermo Relay for damage.
Did the Thermo Relay require replacement?
ÐVerify repairGo to Step 6
6Check the Thermo Relay circuit for a poor connection
at the ECM and replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±172
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1657 (Flash DTC 76)
ECM Main Relay Circuit Open/Short
060RW135
Circuit Description
The ECM main relay circuit receives current through ECM
50A fuse from the battery, current flowing in the order of
the ECM main relay and ECM.
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 P1657 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.

6E±173 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1657 ± ECM Main Relay Circuit Open/Short

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Check the Fuse 50A´ECM and 15A´Eng.
2. If the Fuse is open, replace it as necessary.
Was the Fuse open?
ÐVerify repairGo 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 ªDTCº info for DTC
P1657.
Does the Tech 2 indicate DTC P1657 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check the ECM Main Relay circuit between the Fuse
and the ECM Main Relay for a poor connection and
repair the terminal if necessary.
Did the terminal require repair?
ÐVerify repairGo to Step 5
5Check the ECM Main Relay for a damage and Replace
the ECM (Refer to the Data Programming in Case of
ECM change) Main Relay if necessary.
Did the ECM Main Relay require replacement?
ÐVerify repairGo to Step 6
6Check the ECM Main Relay circuit for a poor
connection at the ECM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 7
7Check the ECM Main Relay Ground circuit for a poor
connection and repair the terminal if necessary.
Did the terminal require repair?
ÐVerify repairGo to Step 8
8Check the ECM Main Relay power circuit for a poor
connection and repair the terminal if necessary.
Did the terminal require repair?
ÐVerify repairGo to Step 9
9Replace the ECM (Refer to the Data Programming in
Case of ECM change) Main Relay.
Is the action complete?
ÐVerify repairGo to Step 10
10Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±174
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1589 (Flash DTC 47)
Transmission SW Circuit Open/Short
060RW131
Circuit Description
The trans mission SW circuit receives current through
ELEC IG 10A fuse from the battery, current flowing in the
order of the trans mission SW and ECM.
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 P1589 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
throttle position display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
If DTC P1589 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
DTC P1589 ± Transmission Circuit Open/Short

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Check the Fuse 10A for a open circuit and replace the
Fuse if necessary.
Did the Fuse require replacement?
ÐVerify repairGo to Step 3