ISUZU AXIOM 2002 Service Repair Manual

6E±84
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Malfunction Indicator Lamp (MIL)
060R200049
Circuit Description
The ªCheck Engineº lamp (MIL) should always be
illuminated and steady with the ignition ªONº and the
engine stopped. Ignition feed voltage is supplied to the
MIL bulb through the meter fuse. The powertrain control
module (PCM) turns the MIL ªONº by grounding the MIL
driver circuit.
Diagnostic Aids
An intermittent MIL may be cased by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:

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

If the engine runs OK, check for a faulty light bulb, an
open in the MIL driver circuit, or an open in the
instrument cluster ignition feed.

If the engine cranks but will not run, check for an open
PCM ignition or battery feed, or a poor PCM to engine
ground.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. A ªNo MILº condition accompanied by a no-start
condition suggests a faulty PCM ignition feed or
battery feed circuit.
9. Using a test light connected to B+, probe each of the
PCM ground terminals to ensure that a good ground
is present. Refer to
PCM Terminal End View for
terminal locations of the PCM ground circuits.
12.In this step, temporarily substitute a known good
relay for the PCM relay. The horn relay is nearby,
and it can be verified as ªgoodº simply by honking
the horn. Replace the horn relay after completing
this step.
17.This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to
PCM
Replacement and Programming Procedures
Powertrain Control Module (PCM) and Sensors.

6E±85
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Malfunction Indicator Lamp (MIL)

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Attempt to start the engine.
Does the engine start?
ÐGo to Step 3Go to Step 6
3Check the meter fuse for the instrument cluster ignition
feed circuit.
Is the fuse OK?
ÐGo to Step 4Go to Step 16
4Ignition ªONº, probe the ignition feed circuit at the
cluster connector with a test light to ground.
Is the test light ªONº?
ÐGo to Step 5Go to Step 13
51. Ignition ªOFFº.
2. Disconnect the PCM.
3. Jumper the MIL driver circuit at the PCM connector
to ground.
4. Ignition ªONº.
Is the MIL ªONº?
ÐGo to Step 10Go to Step 11
6Check the PCM ignition feed and battery feed fuses (15
A engine fuse and 15 A PCM fuse).
Are both fuses OK?
ÐGo to Step 7Go to Step 15
71. Ignition ªOFFº.
2. Disconnect the PCM.
3. Ignition ªONº.
4. Probe the ignition feed circuit at the PCM harness
connector with a test light to ground.
Is the test light ªONº?
ÐGo to Step 8Go to Step 12
8Probe the battery feed circuit at the PCM harness
connector with a test light to ground.
Is the test light ªONº?
ÐGo to Step 9Go to Step 14
9Check for a faulty PCM ground connection.
Was a problem found?
ÐVerify repairGo to Step 10
10Check for damaged terminals at the PCM.
Was a problem found?
ÐVerify repairGo to Step 17
11Check for an open MIL driver circuit between the PCM
and the MIL.
Was a problem found?
ÐVerify repairGo to Step 18
12Substitute a known ªgoodº relay for the PCM main
relay.
Was the malfunction fixed?
ÐVerify repairGo to Step 13
13Repair the open in the ignition feed circuit.
Is the action complete?
ÐVerify repairÐ
14Locate and repair the open PCM battery feed circuit.
Is the action complete?
ÐVerify repairÐ

6E±86
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Malfunction Indicator Lamp (MIL)

 
StepNo Ye s Value(s) Action
15Locate and repair the short to ground in the PCM
ignition feed circuit or PCM battery feed circuit.
Is the action complete?
ÐVerify repairÐ
16Locate and repair the short to ground in the ignition
feed circuit to the instrument cluster, and replace the
fuse.
Is the action complete?
ÐVerify repairÐ
17Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
PCM in ON-Vehicle Service for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ
18Check the MIL driver circuit for a poor connection at the
instrument panel connector.
Was a problem found?
ÐVerify repair
Go to
Instrument
Panel
in
Electrical
Diagnosis

6E±87
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Malfunction Indicator Lamp (MIL) ªONº Steady
060R200049
Circuit description
The malfunction indicator lamp (MIL) should always be
illuminated and steady with ignition ªONº and the engine
stopped. Ignition feed voltage is supplied directly to the
MIL indicator. The powertrain control module (PCM)
turns the MIL ªONº by grounding the MIL driver circuit.
The MIL should not remain ªONº with the engine running
and no DTC(s) set. A steady MIL with the engine running
and no DTC(s) suggests a short to ground in the MIL
driver circuit.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:

Poor connection or damaged harness ± Inspect the
PCM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If the MIL does not remain ªONº when the PCM is
disconnected, the MIL driver wiring is not faulty.
3. If the MIL driver circuit is OK, the instrument panel
cluster is faulty.
6. This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to
PCM
Replacement and Programming Procedures
in
Powertrain Control Module (PCM) and Sensors.

6E±88
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Malfunction Indicator Lamp (MIL) ªONº Steady

StepActionValue(s)Ye sNo
1Was the ªOn-Board diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªOFFº, disconnect PCM.
2. Ignition ªONº, observe the MIL (Service Engine
Soon lamp).
Is the MIL ªONº?
ÐGo to Step 3Go to Step 5
31. Ignition ªOFFº, disconnect the instrument panel
cluster.
2. Check the MIL driver circuit between the PCM and
the instrument panel cluster for a short to ground.
3. If a problem is found, repair as necessary.
Was the MIL driver circuit shorted to ground?
Ð
Go to OBD
System
Check
Go to Step 4
4Replace the instrument panel cluster.
Is the action complete?
Ð
Go to OBD
System
Check
Ð
51. Ignition ªOFFº, reconnect the PCM.
2. Ignition ªONº, reprogram the EEPROM. Refer to
On-Vehicle Service in Powertrain Control Module
and Sensors
for procedures.
3. Using the Tech 2 output controls function, select
MIL dash lamp control and command the MIL
ªOFFº. (Refer to the Miscellaneous test)
Did the MIL turn ªOFFº?
Ð
Go to OBD
System
Check
Go to Step 6
6Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
Ð
Go to OBD
System
Check
Ð

6E±89
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Reduced Power Lamp (RPL)
060R200073
Circuit Description
The Reduced Power lamp (RPL) should always be
illuminated and steady with the ignition ªONº and the
engine stopped. Ignition feed voltage is supplied to the
RPL bulb through the meter fuse. The powertrain control
module (PCM) orders the RPL ªONº signal for Multiplex
Control Unit. When Multiplex Control Unit is received RPL
ªONº signal that turn RPL ªONº by grounding the RPL
driver circuit.
Diagnostic Aids
An intermittent RPL may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:

Inspect the PCM and Multiplex Control Unit harness
and connections for improper mating, broken locks,
improperly formed or damaged terminals, poor
terminal to wire connection, and damaged harness.

If the engine runs OK, check for a faulty light bulb, an
open in the MIL driver circuit, or an open in the
instrument cluster ignition feed.

If the engine cranks but will not run, check for an open
PCM ignition or battery feed, or a poor PCM to engine
ground.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.2. A ªNo RPLº condition accompanied by a no±start
condition suggests a faulty PCM ignition feed or
battery feed circuit.
9. Using a test light connected to B+, probe each of the
Multiplex Control Unit ground terminals to ensure
that a good ground is present. Refer to Multiplex
Control Unit Terminal End View for terminal
locations of the Unit Terminal End View for terminal
locations of the Multiplex Control Unit ground
circuits.
12.Using a test light connected to B+, probe each of
the PCM ground terminals to ensure that a good
ground is present. Refer to PCM Terminal End View
for terminal locations of the PCM ground circuits.
21.In this step, temporarily substitute a known good
relay for the PCM relay. The horn relay is nearby,
and it can be verified as ªgoodº simply by honking
the horn. Replace the horn relay after completing
this step.
24.This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to PCM
Replacement and Programming Procedures in
Powertrain Control Module (PCM) and Sensors.

6E±90
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Reduced Power Lamp (RPL)

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
Performed?
ÐGo to Step 2
Go to OBD
System
Check
2Attempt to start the engine.
Does the engine start?
ÐGo to Step 3Go to Step 11
3Check the following fuses:
MAIN(100A), B+1(60A), B+2(50A), METER(15A),
ECM(15A) , ENGINE(15A)
Was a problem found?
ÐGo to Step 14Go to Step 4
41. Ignition ºOFFº.
2. Disconnect the cluster meter connector.
3. Ignition ªONº, Probe the ignition feed circuit at the
cluster connector with a test light to ground.
Is the test light ªONº?
ÐGo to Step 5Go to Step 15
51. Ignition ªOFFº.
2. Disconnect the Multiplex Control Unit.
3. Check the circuit (Lamp driver Circuit) between
PCM and Multiplex Control Unit.
Was a problem found?
ÐGo to Step 16Go to Step 6
61. Reconnect the cluster meter connector.
2. Disconnect the Multiplex Control Unit.
3. Jumper the RPL driver circuit at the Multiplex
Control Unit connector to ground.
4. Ignition ªONº.
Is the RPL ªONº?
ÐGo to Step 7
Go to
Instrument
Panel in
Electrical
Diagnosis
71. Ignition ªOFFº.
2. Probe the ignition feed circuit at the Multiplex
Control Unit connector with a test light to ground.
3. Ignition ªONº.
Is the test light ªONº?
ÐGo to Step 8Go to Step 17
81. Ignition ªOFFº.
2. Disconnect the PCM.
3. Check the circuit (Lamp driver Circuit) between
PCM and Multiplex Control Unit.
Was a problem found?
ÐGo to Step 18Go to Step 9
9Check the Multiplex Control Unit ground connection
and circuit.
Was a problem found?
ÐGo to Step 19Go to Step 10
10Check for damaged terminals at the Multiplex Control
Unit.
Was a problem found?
ÐGo to Step 20Go to Step 11
111. Ignition ªONº.
2. Probe the ignition feed circuit at the PCM harness
connector with a test light to ground.
Is the test light ªONº?
ÐGo to Step 12Go to Step 21

6E±91
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Reduced Power Lamp (RPL)

 
StepNo Ye s Value(s) Action
121. Ignition ªOFFº.
2. Check for a faulty PCM ground connection and
Circuit.
Was a problem found?
ÐGo to Step 23Go to Step 13
13Check for damaged terminals at the PCM.
Was a problem found?
ÐGo to Step 24Go to Step 25
14Replace the fuse.
Is the action complete?
ÐVerify repairÐ
15Locate and repair the cluster meter battery feed open
circuit.
Is the action complete?
ÐVerify repairÐ
16Locate and repair the circuit between cluster meter and
Multiplex Control Unit open circuit.
Is the action complete?
ÐVerify repairÐ
17Locate and repair the circuit Multiplex Control Unit
battery feed open circuit.
Is the action complete?
ÐVerify repairÐ
18Locate and repair the between Multiplex Control Unit
and PCM open circuit.
Is the action complete?
ÐVerify repairÐ
19Locate and repair the ground connection for Multiplex
Control Unit circuit.
Is the action complete?
ÐVerify repairÐ
20Reconnect the Multiplex Control Unit. circuit.
Is the action complete?
ÐVerify repairÐ
21Substitute a known ªgoodº relay for the PCM main
relay.
Was the malfunction fixed?
ÐVerify repairGo to Step 22
22Repair the open in the ignition feed circuit.
Is the action complete?
ÐVerify repairÐ
23Locate and repair the ground connection for PCM
circuit.
Is the action complete?
ÐVerify repairÐ
24Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed.
Refer to ON-Vehicle Service in Power Control Module
and Sensors for procedures.
And also refer to latest Service Bulletin.
Check to see if the latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±92
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
No Reduced Power Lamp (RPL)

 
StepNo Ye s Value(s) Action
251. Ignition ªOFFº.
2. Reconnect all connectors.
3. Install the Tech 2.
4. Ignition ªONº.
5. Using the Tech 2 output controls function, select
RPL dash lamp control and command the RPL
ªONº. (Refer to the Miscellaneous test)
Did the RPL turn ªONº?
ÐVerify repairGo to Step 26
261. Ignition ªOFFº.
2. Disconnect the PCM.
3. Check the circuit (DLC line) between PCM and
DLC.
Was a problem found?
ÐGo to Step 27Go to Step 24
27Locate and repair the circuit the between PCM and
DLC.
Is the action complete?
ÐGo to Step 25Ð

6E±93
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Reduced Power Lamp (RPL) ªONº Steady
060R200073
Circuit Description
The Reduced Power lamp (RPL) should always be
illuminated and steady with the ignition ªONº and the
engine stopped. Ignition feed voltage is supplied to the
RPL bulb through the meter fuse. The powertrain control
module (PCM) orders the RPL ªONº signal for Multiplex
Control Unit. When Multiplex Control Unit is received RPL
ªONº signal that turn RPL ªONº by grounding the RPL
driver circuit.
The RPL should not remain ªONº with the engine running
and no DTC(s) set. A steady RPL with the engine running
and no DTC(s) suggests a short to ground in the RPL
driver circuit.
Diagnostic Aids
An intermittent RPL may be caused by a poor connection,
rubbed through wire insulation, or a wire broken inside the
insulation. Check for the following items:
Poor connection or damaged harness ± Inspect the
PCM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal to wire connection, and
damaged harness.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If the RPL does not remain ªONº when the Multiplex
Control Unit is disconnected, the RPL driver wiring
is not faulty.
3. If the RPL driver circuit is OK, the instrument panel
cluster is faulty.
10. This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to PCM
Replacement and Programming Procedures in
Powertrain Control Module (PCM) and Sensors.