check engine ISUZU TROOPER 1998 Service Repair Manual

6E±219 ENGINE DRIVEABILITY AND EMISSIONS

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

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Tech 2 display related to DTC P0355 while moving theconnector and wiring related to the ignition system. A
change in the display will indicate the location of the
fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
DTC P0355 ± Ignition 5 Control 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 Record
conditions as noted.
4. Use a Tech 2 to monitor the ªSpecific DTCº
information for DTC P0355 until the DTC P0355 test
runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0355 failed this ignition
cycle?
ÐGo to Step 3
Go to
Diagnostic
Aids
3Check for faulty connection at ignition coil.
Was a problem found?
ÐVerify repairGo to Step 4
4Check for faulty connection at PCM connector.
Was a problem found?
ÐVerify repairGo to Step 5
51. Ignition ªON,º engine ªOFF.º
2. Back probe the ignition control circuit 5 at the PCM
with a DVM positive lead with the negative lead to
ground.
Is the voltage near the specified value?
25-55 mVGo to Step 6Go to Step 9
61. Ignition ªON,º engine running.
2. Back probe the ignition control circuit at the PCM for
the cylinder being tested.
Is the voltage in the specified range, rapidly toggling
back and forth to a reading 20-50 mV higher?
100-180 mVGo to Step 7Go to Step 13
71. Ignition ªOFF.º
2. Disconnect the 3-pin and 5-pin connectors at the
ignition coil.
3. Check ignition control circuit 5 voltage at the ignition
coil connector while cranking the engine.
Does the voltage measure between the specified
values?
200-1200 mVGo to Step 8Go to Step 11
8Replace the ignition coil.
Is the action complete?
ÐVerify repairÐ
91. Ignition ªOFF.º
2. Disconnect the PCM and the ignition coil.
3. Check ignition control circuit 5 for short to ground.
Was a problem found?
ÐVerify repairGo to Step 10
10Check ignition control circuit 5 for short to voltage.
Was a problem found?
ÐVerify repairGo to Step 13

6E±220
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0355 ± Ignition 5 Control Circuit

 
StepNo Ye s Value(s) Action
11Check for an open ignition control circuit 1.
Was the ignition control circuit open?
ÐGo to Step 12Go to Step 13
12Repair the open ignition control circuit.
Is the action complete?
ÐVerify repairÐ
13Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±221 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0356 Ignition 6 Control Circuit
D06RW072
Circuit Description
The powertrain control module's (PCM) control circuit 6
provides a zero-volt or a 5-volt output signal to the ignition
coil. The normal voltage on the circuit is zero volts. When
the ignition coil receives the 5-volt signal from the PCM, it
provides a ground path for the B+ supply to the primary
side of the number 6 ignition coil. When the PCM shuts off
the 5 volts to the ignition coil, the ignition coil turns ªOFF.º
This causes the ignition coil primary magnetic field to
collapse, producing a voltage in the secondary coil which
fires the spark plug.
The circuit between the PCM and ignition coil is monitored
for an open circuit, short to voltage, and short to ground.
When the PCM detects a problem on ignition control
circuit 6, it will set a DTC P0356.
Conditions for Setting the DTC

The ignition is ªON.º

The engine is turning, determined by the 58X
crankshaft position input signal.
The output voltage is not equal to 5 volts when output
is ªON.º

The output voltage is not equal to 0 volts when output
is ªOFF.º

Twenty test failures occur within 40 samples of
continuous circuit monitoring.
Action Taken When the DTC Sets

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

The PCM 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 P0356 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

6E±222
ENGINE DRIVEABILITY AND EMISSIONS

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

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Tech 2 display related to DTC P0356 while moving theconnector and wiring related to the ignition system. A
change in the display will indicate the location of the
fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
DTC P0356 ± Ignition 6 Control 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 Record
conditions as noted.
4. Use a Tech 2 to monitor the ªSpecific DTCº
information for DTC P0356 until the DTC P0356 test
runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0356 failed this ignition
cycle?
ÐGo to Step 3
Go to
Diagnostic
Aids
3Check for faulty connection at ignition coil.
Was a problem found?
ÐVerify repairGo to Step 4
4Check for faulty connection at PCM connector.
Was a problem found?
ÐVerify repairGo to Step 5
51. Ignition ªON,º engine ªOFF.º
2. Back probe the ignition control circuit 6 at the PCM
with a DVM positive lead with the negative lead to
ground.
Is the voltage near the specified value?
25-55 mVGo to Step 6Go to Step 9
61. Ignition ªON,º engine running.
2. Back probe the ignition control circuit at the PCM for
the cylinder being tested.
Is the voltage in the specified range, rapidly toggling
back and forth to a reading 20-50 mV higher?
100-180 mVGo to Step 7Go to Step 13
71. Ignition ªOFF.º
2. Disconnect the 3-pin and 5-pin connectors at the
ignition coil.
3. Check ignition control circuit 6 voltage at the ignition
coil connector while cranking the engine.
Does the voltage measure between the specified
values?
200-1200 mVGo to Step 8Go to Step 11
8Replace the ignition coil.
Is the action complete?
ÐVerify repairÐ
91. Ignition ªOFF.º
2. Disconnect the PCM and the ignition coil.
3. Check ignition control circuit 6 for short to ground.
Was a problem found?
ÐVerify repairGo to Step 10
10Check ignition control circuit 6 for short to voltage.
Was a problem found?
ÐVerify repairGo to Step 13

6E±223 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0356 ± Ignition 6 Control Circuit

 
StepNo Ye s Value(s) Action
11Check for an open ignition control circuit 1.
Was the ignition control circuit open?
ÐGo to Step 12Go to Step 13
12Repair the open ignition control circuit.
Is the action complete?
ÐVerify repairÐ
13Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±224
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0402 EGR Pintle Crank Error
D06RW106
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is stuck open. If the PCM
detects a pintle position signal indicates more than 21.5%
and more than for 625 msec during cranking, the PCM will
set DTC P0402.
Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

Intake Air temp is more than 3
C

At Engine revolution less than 600 RPM, EGR pintle
position indicates more than 21.5% and more than for
625 msecs.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The PCM 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 P0402 can be cleared by using Tech 2 ªClear Infoº
function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Foreign material on EGR valve between pintle and
seat may cause EGR stuck open. Inspect foreign
material in EGR valve.

Excessive carbon deposit may cause unsmooth
operation of EGR valve shaft. Inspect carbon deposit
and clean up inside of carbon deposit.

Poor connection or damaged harness±inspect the
wiring harness for damage If the harness appears to be
OK, observe the EGR actual position display on Tech
2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.
NOTE: If the EGR valve shows signs of excessive heat,
check the exhaust system for blockage (possibly a
plugged catalytic converter) using the ªRestricted
Exhaust System Checkº.

6E±225 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0402 ± EGR Pintle Crank Open Error

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine ªOFFº, review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using Tech 2, monitor ªSpecific DTCº info for DTC
P0402 until the DTC P0402 test runs. Note the
result.
Does Tech 2 indicates DTC P0402 failed this ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
ÐGo to Step 4Go to Step 5
4Repair the damaged pin or terminal.
Is the action complete?
ÐVerify repairÐ
51. Remove EGR valve from Engine.
2. Inspect EGR valve whether there is any foreign
material between seat and pintle.
Was any foreign material in EGR valve?
ÐGo to Step 6Go to Step 7
61. Remove EGR valve foreign material from EGR
valve and clean up inside.
2. Visually inspect damage of pintle and seat, which
leakage may occur.
Was there any severe damage which affects function?
ÐGo to Step 7
Verify repair
Go to
Step 8
71. Reconnect.
2. Ignition ªOFFº.
3. Install Tech 2.
4. Run the engine at idle.
5. On Tech-II, select special function for EGR.
6. Use the ªUPº arrow to increase the EGR from 0% to
40%.
Did EGR work properly?
ÐÐGo to Step 8
8Replace the EGR valve.
Does DTC P0402 still fail ªDTCº test on Tech 2?
ÐGo to Step 9Verify repair
9Replace the EGR valve.
Is the action complete?
ÐVerify repairÐ

6E±226
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0404 EGR Open Stuck
D06RW106
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is different from
commanded position. If the PCM detects a pintle position
signal indicates more than 15 points different between
current and commanded and more than 15 seconds, the
PCM will set DTC P0404.
Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

Intake Air temp is more than 3
C.

Desire EGR position is more than 0.

The difference between desired EGR and current EGR
is less than 3%.

Difference EGR pintle position between current and
commanded position becomes more than 15% and
last more than 15 seconds, and this condition meets
three times in a trip. Then it trigger, the PCM lights on.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected after consecutive 2nd
trip in which the fault is detected.
The PCM 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 Tech 2 ªClear Infoº
function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Excessive carbon deposit on EGR valve shaft may
cause EGR stuck open or unsmooth operation. Those
carbon deposit may occur by unusual port operation.
Clean up carbon may make smooth function of EGR
valve.

Poor connection or damaged harness ± Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E±227 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0404 ± EGR Open Stuck

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 ªOFFº, review and record
Tech 2 Failure Records Data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using Tech 2, monitor ªSpecific DTCº info for DTC
P0404 until the DTC P0404 test runs. Note the
result.
Does Tech 2 indicates DTC P0404 failed this ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
ÐGo to Step 4Go to Step 5
4Repair the damaged pin or terminal.
ÐVerify repair
Is the action
complete?
51. Remove EGR valve from Engine.
2. Inspect EGR valve whether there is any excessive
carbon deposit on EGR shaft.
Was excessive carbon deposit 0n EGR valve shaft?
ÐGo to Step 6Go to Step 7
61. Clean up EGR valve shaft and inside of EGR valve.
2. Visually inspect damage of pintle and seat whether
there is bent, leakage may occur.
Was there any severe damage which affects function?
ÐGo to Step 8
Verify repair
Go to
Step 7
71. Reconnect.
2. Ignition ªOFFº.
3. Install Tech 2.
4. Run the engine at idle.
5. On Tech 2, select F3:Misc. Test; F2:EGR.
6. Use the ªUPº arrow to increase the EGR from 0% to
40%.
Did EGR work properly?
ÐÐGo to Step 8
8Replace the EGR valve.
Does DTC P0404 still fail ªDTCº test on Tech 2?
ÐGo to Step 9Verify repair
9Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±228
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0405 EGR Low Voltage
D06RW106
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the PCM. If current
pintle position voltage indicates less than 0.1 V and last
more than 10 seconds, then the PCM will set DTC P0405.
Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

EGR pintle position output voltage is less than 0.1 volt
and last more than 10 sec. Action taken when the DTC
sets.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.
The PCM 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 Tech 2 ªClear Infoº
function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness ± Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.