Opel Frontera UBS. Manual - part 292

6E–74

ENGINE DRIVEABILITY AND EMISSIONS

No Malfunction Indicator Lamp (MIL)

D06RW00006

Circuit Description

The “Check Engine” lamp (MIL) should always be
illuminated and steady with the ignition “ON” 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 “ON” 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 “No MIL” 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 “good” simply by honking
the horn. Replace the horn relay after completing
this step.

6E–75

ENGINE DRIVEABILITY AND EMISSIONS

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

UBS

98 model year Immobilizer Workshop Manual.

No Malfunction Indicator Lamp (MIL)

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Attempt to start the engine.

Does the engine start?

—

Go to

Step 3

Go to

Step 6

Check the meter fuse for the instrument cluster ignition
feed circuit.

Is the fuse OK?

—

Go to

Step 4

Go to

Step 16

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

Is the test light “ON?”

—

Go to

Step 5

Go to

Step 13

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

to ground.

4. Ignition “ON.”

Is the MIL “ON?”

—

Go to

Step 10

Go to

Step 11

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

Are both fuses OK?

—

Go to

Step 7

Go to

Step 15

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

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

Check for a faulty PCM ground connection.

Was a problem found?

—

Verify repair

Go to

Step 10

Check for damaged terminals at the PCM.

Was a problem found?

—

Verify repair

Go to

Step 17

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

Was a problem found?

—

Verify repair

Go to

Step 18

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

Was the malfunction fixed?

—

Verify repair

Go to

Step 13

Repair the open in the ignition feed circuit.

Is the action complete?

—

Verify repair

—

6E–76

ENGINE DRIVEABILITY AND EMISSIONS

No Malfunction Indicator Lamp (MIL)

(Cont'd)

Step

Yes

Value(s)

Action

Locate and repair the open PCM battery feed circuit.

Is the action complete?

—

Verify repair

—

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

Is the action complete?

—

Verify repair

—

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

Is the action complete?

—

Verify repair

—

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

PCM in ON-Vehicle Service for

procedures.

Is the action complete?

—

Verify repair

—

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

Was a problem found?

—

Verify repair

Go to

Instrument

Panel in

Electrical

Diagnosis

6E–77

ENGINE DRIVEABILITY AND EMISSIONS

Malfunction Indicator Lamp (MIL) “ON” Steady

D06RW00007

Circuit description

The malfunction indicator lamp (MIL) should always be
illuminated and steady with ignition “ON” and the engine
stopped. Ignition feed voltage is supplied directly to the
MIL indicator. The powertrain control module (PCM)
turns the MIL “ON” by grounding the MIL driver circuit.
The MIL should not remain “ON” 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 “ON” 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

UBS

98 model year Immobilizer Workshop Manual.

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