Opel Frontera UBS. Manual - part 2357

6E–464

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Detonation/Sparks Knock Symptoms

  (Cont'd)

Step

No

Yes

Value(s)

Action

10

1. Disconnect the ignition coil.

Is the action complete?

—

Go to 

Step 11

—

11

Check the ION sensing harness between the ignition
coil and ION sensing module circuit at the DC motor
harness connector.

Was a problem found?

—

Verify repair

Go to 

Step 12

12

Check the following items;

1. Ignition coil and ignition coil circuit.
2. Ignition coil ground circuit for a poor connection.
3. If a problem is found, repair wiring harness as

necessary.

Was a problem found?

—

Verify repair

Go to 

Step 13

13

Replace the Ignition coil.

Is the action complete?

—

Verify repair

Go to 

Step 14

14

Check the following items;

1. ION sensing module ground circuit for a poor

connection.

2. If a problem is found, repair wiring harness as

necessary.

Was a problem found?

—

Go to 

Step 10

Go to 

Step 15

15

Replace the ION sensing module.

Is the action complete?

—

Verify repair

Go to 

Step 16

16

1. Check fuel pressure.  Refer to Chart  Fuel System

Pressure Test.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 17

17

1. Check items that can cause an engine to run lean

(long term fuel trim significantly in the positive
range).  For a lean condition, refer to 

Diagnostic

Aids in DTC P0171 Diagnostic Support.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 18

18

1. Spark plugs for proper heat range.  Refer to 

General

Information.

2. If incorrect spark plugs are installed, replace spark

plugs as necessary.

Did any spark plugs require replacement?

—

Verify repair

Go to 

Step 19

19

1. Remove excessive carbon buildup with a top engine

cleaner.  Refer to instructions on the top engine
cleaner can.

2. Re-evaluate vehicle performance.

Is detonation still present?

—

Go to 

Step 20

Verify repair

6E–465

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Detonation/Sparks Knock Symptoms

  (Cont'd)

Step

No

Yes

Value(s)

Action

20

1. Check for an engine mechanical problem.  Perform

a cylinder compression check.  Refer to 

Engine

Mechanical.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 21

21

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

D

Visual/physical inspection

D

Tech 2 data

D

Freeze Frame data/Failure Records buffer

D

All electrical connections within a suspected
circuit and/or system.

3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E–466

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Rough, Unstable, or Incorrect Idle, Stalling Symptom

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Engine runs unevenly at idle.  If severe, the engine or
vehicle may shake.  Engine idle speed may vary in
RPM.   Either condition may be severe enough to stall
the engine.

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Was the “Electric Throttle Control (ETC) System
Check” performed?

—

Go to 

Step 3

Go to 

ETC

System

Check

3

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Go to 

Step 14

Go to 

Step 4

4

Was a visual/physical check performed?

—

Go to 

Step 5

Go to 

Visual/

Physical

Check

5

1. Check the PCM grounds for cleanliness, tightness

and proper routing.  Refer to the PCM wiring
diagrams in 

Electrical Diagnosis.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step  6

6

Observe the long term fuel trim on the Tech 2.

Is the long term fuel trim significantly in the negative
range (rich condition)?

—

Go to 

Step 7

Go to 

Step 8

7

1. Check items that can cause the engine to run rich.

Refer to 

Diagnostic Aids in DTC P0172 Diagnostic

Support.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 10

8

Is the long term fuel trim significantly in the positive
range (lean condition)?

—

Go to 

Step 9

Go to 

Step 10

9

1. Check items that can cause the engine to run lean.

Refer to 

Diagnostic Aids in DTC P0171 Diagnostic

Support.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 10

10

1. Check for incorrect idle speed.  Ensure that the

following conditions are present:

D

The engine is fully warm.

D

The accessories are “OFF”.

2. Using a Tech 2, monitor the Engine Speed.

Is the Engine Speed within the specified values?

Desired Idle

Speed

Go to 

Step 12

Go to 

Step 11

6E–467

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Rough, Unstable, or Incorrect Idle, Stalling Symptom

  (Cont'd)

Step

No

Yes

Value(s)

Action

11

1. Visually/physically inspect for the following

conditions:

D

Restricted air intake system.  Check for a
possible collapsed air intake duct, restricted
air filter element, or foreign objects blocking
the air intake system.

D

Large vacuum leak.  Check for a condition that
causes a large vacuum leak, such as an
incorrectly installed or faulty crankcase
ventilation valve or a disconnected brake
booster hose.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 9

12

Check the injector connections.  If any of the injectors
are connected to an incorrect cylinder, correct as
necessary.

Was a problem found?

—

Verify repair

Go to 

Step 13

13

1. Perform the “Injector Coil/Balance Test” in 

Fuel

Metering System.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 14

14

1. Check for fuel in the pressure regulator vacuum

hose.

2. If fuel is present, replace the fuel pressure regulator

assembly.  Refer to 

Fuel Metering System.

3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 15

15

1. Check for proper ignition voltage output with spark

tester J 26792 (ST-125).  Refer to 

Electronic Ignition

System for the procedure.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 16

16

1. Remove spark plugs.  Check for wet plugs, cracks,

wear, improper gap, burned electrodes, or heavy
deposits.  Refer to 

Electronic Ignition System.

NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 17

17

1. Check for a loose ignition coil ground and ION

Sensing Module circuit.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 18

18

1. Check ignition coils for cracks or carbon tracking.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 19