1998 ISUZU TROOPER sensor

6E±131 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1403 ± EGR EVRV Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Check the EVRV circuit.
Was the EVRV circuit darmage?
Ð
Replace the
EVRV circuit
Go to Step 3
31. Start the engine.
2. Monitor the MAP signal with a scan tool while idling.
3. While idling, jab the accelerator pedal about halfway
down and immediately let the engine return to idle.
Did the MAP value on the scan tool show an immediate
large change?
ÐGo to Step 5Go to Step 4
4Replace the MAP sensor.
Is the action complete?
ÐVerify repairÐ
51. Inspect the exhaust system for modification of
original installed parts or leaks.
2. If a problem was found, repair exhaust system as
necessary.
Was a condition present that required repair?
ÐGo to Step 8Go to Step 6
61. Remove the EGR valve.
2. Visually and physically inspect the pintle, valve
passages and the adapter for excessive deposits or
any kind of a restriction.
3. If a problem is found, clean or replace EGR system
components as necessary.
Was a condition present that required repair?
ÐGo to Step 8Go to Step 7
71. Inspect the EGR passages for a blockage caused
by excessive deposits or other damage.
2. If a problem is found, correct the condition as
necessary.
Was a condition present that required repair?
ÐGo to Step 8
Refer to
Diagnostic
Aids
81. Review and record the scan tool Failure Records
data.
2. Clear DTC and monitor the scan tool System Info
Screen while operating the vehicle as specified in
ªDiagnostic Aids.º
3. Using a scan tool, monitor ªDTCº info for DTC
P1403 until the DTC P1403 test runs.
4. Note the test result.
Does the scan tool indicate DTC P1403 failed this
ignition?
Ð
Go to the last
step
completed in
this
diagnostic
chart
Repair
complete

6E±134
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0405 (Flash DTC 26)
EGR Pressure Sensor Low Voltage
060RW134
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.

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

DTC P0405 can be cleared by using the scan tool
ªClear Infoº function or by disconnecting the ECM
battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness ± Inspect the
wiring harness for damage.
DTC P0405 ± EGR Pressure 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
2Put the engine into an idling status.
Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?
0.25 VGo to Step 3
Refer to
Diagnostic
Aids
andSymp
tom
Diagnosis

6E±135 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0405 ± EGR Pressure Sensor Low Voltage

 
StepNo Ye s Value(s) Action
31. Turn off the ignition switch.
2. Remove the sensor connector connection.
3. Jumper between harness pins ªredº and ªblueº
wires.
4. Turn on the ignition switch ªONº.
Is the EGR pressure sensor voltage reading above the
specified value?
4 VGo to Step 5Go to Step 4
41. Turn off the ignition switch.
2. Remove the jumper wire.
3. Connect the relay & solenoid checker
(5-8840-0386-0) to the battery voltage, then check
the EGR pressure sensor signal circuit (blue wire).
4. Turn on the ignition switch.
Is the value displayed on the Tech 2 above the specified
value?
4 VGo to Step 6Go to Step 7
5Check the terminal connection at the EGR pressure
sensor and repair or replace terminal if necessary.
Is the action complete?
ÐVerify repairÐ
6Repair the 5V power circuit (red) harness or Replace
the ECM (Refer to the Data Programming in Case of
ECM change).
Is the action complete?
ÐVerify repairÐ
7Repair the signal circuit (blue) harness or Replace the
ECM (Refer to the Data Programming in Case of ECM
change).
Is the action complete?
ÐVerify repairÐ

6E±136
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1405 (Flash DTC 37)
EGR EVRV Circuit Open/Short
060RW135
Circuit Description
EGR EVRV Circuit has a common power source in
parallel with EGR, VSV, RPCV, and Intake Throttle Motor.
This may cause multiple DTCs. On such occasion, refer
to ªMultiple ECM Information Sensor DTCs Setº.
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 P1405 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation or a wire broken inside the
insulation. Check for:

Poor connection ± Inspect the ECM harness and
connectors for improper mating, broken locks,
improperly formed or damaged terminals, and poor
terminal-to-wire connection.

Damaged harness ± Inspect the wiring harness for
damage.

6E±138
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0406 (Flash DTC 26)
EGR Pressure Sensor High Voltage
060RW134
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.

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

DTC P0404 can be cleared by using the scan tool
ªClear Infoº function or by disconnecting the ECM
battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness ± Inspect the
wiring harness for damage.
DTC P0406 ± EGR Pressure 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
2Put the engine into an idling status.
Is the EGR pressure sensor 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 EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?
1 VGo to Step 5Go to Step 6

6E±139 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 ± EGR Pressure Sensor High Voltage

 
StepNo Ye s Value(s) Action
4Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?
1 V
Refer to
Chart P0107
Refer to
Diagnostic
Aids
andSymp
tom
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 EGR pressure sensor hose or the EGR
pressure sensor.
Is the action complete?
ÐVerify repairÐ
8Repair the harness for open ground circuit.
Is the action complete?
ÐVerify repairÐ

6E±144
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1485 (Flash DTC 74)
ITP (Intake Thorottle Position) Sensor Low Voltage
060RW134
Circuit Description
The intake throttle position (ITP) sensor circuit provides a
voltage signal that changes relative to throttle blade
angle.
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 P1485 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 ITP sensor. A change in the display will
indicate the location of the fault.
If DTC P1485 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 P1485 ±ITP 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. With the throttle closed by the hand, observe the
ªITP Sensorº display on the Tech 2.
Is the ªITP Sensorº below the specified value?
0.22 VGo to Step 4Go to Step 3

6E±145 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1485 ±ITP Sensor Low Voltage

 
StepNo Ye s Value(s) Action
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
P1485.
Does the Tech 2 indicate DTC P1485 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check the ITP sensor signal circuit for a poor
connection at the ECM and replace the terminal if
necessary.
Did the terminal 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 ªSpecific DTCº info for
DTC P1485.
Dose the Tech 2 indicate DTC P1485 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