ISUZU TROOPER 1998 Service Repair Manual

6E±158
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1510 ± Idle SW Malfunction, Short Circuit

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
P1510.
Does the Tech 2 indicate DTC P1510 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
3Check the Idle SW circuit for a poor connection and
repair the terminal if necessary.
Did the terminal require repair?
ÐVerify repairGo to Step 4
41. Ignition ªON.º
2. Operate the accel pedal, and check the data list ªON
OFFº on the Tech 2.
Is the data list correct?
ÐVerify repairGo to Step 5
5Replace the Idle SW.
Is the action complete?
ÐVerify repairÐ

6E±159 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0562 (Flash DTC 35)
System Voltage Too Low
Circuit Description
The engine control module (ECM) monitors the system
voltage on the ignition feed terminals to the ECM. A
system voltage DTC will set whenever the voltage is
above a calibrated value.
Action Taken When the DTC Sets

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

The ECM will store as Failure Records only conditions
which were present when the DTC was set. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC

DTC P0563 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
If the DTC sets when an accessory is operated, check for
a poor connection or defective accessory.
DTC P0562 ± System Voltage Too Low

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Using a DVM, measure the battery voltage at the
battery.
Is the battery voltage greater than the specified value?
11.5 VGo to Step 3
Charge
battery, then
go to
Step 3
31. Install a Tech 2.
2. Select ªIgnition Voltsº on the Tech 2.
3. Start the engine and raise the engine speed to the
specified value.
4. Load the electrical system by turning on the
headlights, high blower, etc.
Is the ignition voltage approximately equal to the
specified value?
2000 RPM
12.8-14.1 V
Go to Step 4
Go to
Starting/
Charging
41. Ignition ªOFF.º
2. Disconnect the ECM connector at the ECM.
3. Using a DVM, measure the battery voltage at the
ECM connector.
Is it approximately equal to battery voltage?
Ð
Check for
excessive
current draw
with ignition
ªOFF,º engine
ªOFF.º
Go to Step 5
51. Check for faulty connections at the ECM harness
terminals.
2. Repair as necessary.
Was a repair necessary?
ÐVerify repairGo to Step 6
6Check for an open battery feed circuit to the ECM.
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±160
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1562 (Flash DTC 35)
System Voltage Too Low at Cranking
Circuit Description
The engine control module (ECM) monitors the system
voltage on the ignition feed terminals to the ECM. A
system voltage DTC will set whenever the voltage is
above a calibrated value.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) at the first time of the fault is detected.
Conditions for Clearing the MIL/DTC

DTC P0563 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
If the DTC sets when an accessory is operated, check for
a poor connection or defective accessory.
DTC P1562 ± System Voltage Too Low at Cranking

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Using a DVM, measure the battery voltage at the
battery.
Is the battery voltage less than the specified value?
11.5 VGo to Step 3Go to Step 4
31. Charge the battery and clean the battery terminals.
2. Clean the battery ground cable connection if
corrosion is indicated.
Is the battery voltage less than the specified value?
11.5 V
Replace
battery
Go to Step 4
41. Turn ªOFFº all the accessories.
2. Install a Tech 2.
3. Select the ignition voltage parameter on the Tech 2.
4. Start the engine and raise the engine RPM to the
specified value.
Is the voltage more than 2.5 volts greater than the
measurement taken in step 2 or 3?
2000 RPM
Go to
Starting/Char
ging
Go to Step 5
5Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ

6E±161 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1587 (Flash DTC 25)
Brake SW Malfunction
060RW130
Circuit Description
Brake Stop Lamp SW Circuit receives through Stop Lamp
10A fuse from the battery.
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 P1587 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
Brake SW display on the Tech 2 while moving
connectors and wiring harnesses related to the Brake
SW. A change in the display will indicate the location
of the fault.
If DTC P1587 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±162
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1587 ± Brake SW Malfunction

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
P1587.
Does the Tech 2 indicate DTC P1587 failed?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Check the Brake SW circuit for a poor connection and
replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 4
4Replace the Brake SW.
Is the action complete?
ÐVerify repairÐ

6E±163 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1588 (Flash DTC 25)
Brake SW Malfunction
060RW130
Circuit Description
Brake Stop Lamp SW Circuit receives through Stop Lamp
10A fuse from the battery.
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 P1588 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
Brake SW display on the Tech 2 while moving
connectors and wiring harnesses related to the Brake
SW. A change in the display will indicate the location
of the fault.
If DTC P1588 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±164
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1588 ± Brake SW Malfunction

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
P1588.
Does the Tech 2 indicate DTC P1588 failed?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Check the Brake SW circuit for a poor connection and
replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 4
4Replace the Brake SW.
Is the action complete?
ÐVerify repairÐ

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