Isuzu Trooper (2000 year). Manual - part 241

6E–93

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Malfunction Indicator Lamp (MIL) “ON” Steady

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Ignition “OFF,” disconnect PCM.
2. Ignition “ON,” observe the MIL (Service Engine

Soon lamp).

Is the MIL “ON?”

—

Go to 

Step 3

Go to 

Step 5

3

1. Ignition “OFF,” 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?

—

Go to 

OBD

System

Check

Go to 

Step 4

4

Replace the instrument panel cluster.

Is the action complete?

—

Go to 

OBD

System

Check

—

5

1. Ignition “OFF,” reconnect the PCM.
2. Ignition “ON,” 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
“OFF.” (Refer to the Miscellaneous test)

Did the MIL turn “OFF?”

—

Go to 

OBD

System

Check

Go to 

Step 6

6

Replace 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?

—

Go to 

OBD

System

Check

—

6E–94

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

No Reduced Power Lamp (RPL)

D06RY00127

Circuit Description

The Reduced Power lamp (RPL) should always be
illuminated and steady with the ignition “ON” and the
engine stopped. Ignition feed voltage is supplied to the
RPL bulb through the meter fuse. The powertrain control
module (PCM) turns the RPL “ON” by grounding the RPL
driver circuit.

Diagnostic Aids

An intermittent RPL may be cased by a poor connection,
rubbed - through wire insulation, or a wire broken inside
the insulation. Check for the following items:

D

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

D

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.

D

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 “ No RPL”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 toPCM 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 “good” 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 in
Powertrain Control Module (PCM) and Sensors.

6E–95

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

No Reduced Power Lamp (RPL)

 

Step

Action

Value(s)

Yes

No

1

Was the “On - Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Attempt to start the engine.

Does the engine start?

—

Go to 

Step 3

Go to 

Step 6

3

Check the meter fuse for the instrument cluster
ignitionfeed circuit.

Is the fuse OK?

—

Go to 

Step 4

Go to 

Step 16

4

Ignition “ON,” probe the ignition feed circuit at
thecluster connector with a test light to ground.

Is the test light “ON?”

—

Go to 

Step 5

Go to 

Step 13

5

1. Ignition “OFF.”
2. Disconnect the PCM.
3. Jumper the RPL driver circuit at the PCM connector

to ground.

4. Ignition “ON.”

Is the RPL “ON?”

—

Go to 

Step 10

Go to 

Step 11

6

Check the PCM ignition feed and battery feed fuses
(15A engine fuse and 15 A PCM fuse).

Are both fuses OK?

—

Go to 

Step 7

Go to 

Step 15

7

1. Ignition “OFF.”
2. Disconnect the PCM.
3. Ignition “ON.”
4. Probe the ignition feed circuit at the PCM harness

connector with a test light to ground.

Is the test light “ON?”

—

Go to 

Step 8

Go to 

Step 12

8

Probe the battery feed circuit at the PCM harness
connector with a test light to ground.

Is the test light “ON?”

—

Go to 

Step 9

Go to 

Step 14

9

Check for a faulty PCM ground connection.

Was a problem found?

—

Verify repair

Go to 

Step 10

10

Check for damaged terminals at the PCM.

Was a problem found?

—

Verify repair

Go to 

Step 17

11

Check for an open RPL driver circuit between the PCM
and the RPL.

Was a problem found?

—

Verify repair

Go to

Step 18

12

Substitute a known “good” relay for the PCM mainrelay.

Was the malfunction fixed?

—

Verify repair

Go to 

Step 13

13

Repair the open in the ignition feed circuit.
Is the action complete?

—

Verify repair

—

14

Locate and repair the open PCM battery feed circuit.

Is the action complete?

—

Verify repair

—

6E–96

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

No Reduced Power Lamp (RPL)

  (Cont'd)

Step

No

Yes

Value(s)

Action

15

Locate and repair the short to ground in the PCM
ignition feed circuit or PCM battery feed circuit.

Is the action complete?

—

Verify repair

—

16

Locate and repair the short to ground in the ignition
feed circuit to the instrument cluster, and replace
thefuse.

Is the action complete?

—

Verify repair

—

17

Replace 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 PROGRMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

18

Check the RPL driver circuit for a poor connection at
the instrument panel connector.

Was a problem found?

—

Verify repair

Go to

Instrument

Panel in

Electrical

Diagnosis