Opel Frontera UBS. Manual - part 1228

6E–278

ENGINE DRIVEABILITY AND EMISSIONS

Excessive Exhaust Emissions or Odors Symptom

  (Cont'd)

Step

No

Yes

Value(s)

Action

13

Does the exhaust emission test indicate excessive CO
and HC levels or is long term fuel trim significantly in the
negative range (rich condition)?

—

Go to 

Step 14

Go to 

Step 15

14

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

Refer to 

Diagnostic Aids in DTC P0172 Diagnostic

Support.  Make any necessary repairs.

2. Perform the exhaust emission test.

Does the vehicle pass the test?

—

System OK

Go to 

Step 16

15

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

Refer to 

Diagnostic Aids in DTC P0171 Diagnostic

Support.  Make any necessary repairs.

2. Perform the exhaust emission test.

Does the vehicle pass the test?

—

System OK

Go to 

Step 16

16

1. Check the EGR system.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Go to 

Step 12

Go to 

Step 17

17

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?

—

Go to 

Step 12

Go to 

Step 18

18

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 butter

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–279

ENGINE DRIVEABILITY AND EMISSIONS

Dieseling, Run-On Symptom

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Engine continues to run after key is turned “OFF,” but
runs very rough.  If engine runs smooth, check ignition
switch and adjustment.

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

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?

—

Verify repair

Go to 

Step 3

3

Was a visual/physical check performed?

—

Go to 

Step 4

Go to

Visual/Physic

al Check

4

1. Check for a short between B+ and any of the ignition

feed circuits.

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

Was a problem found?

—

Verify repair

Go to 

Step 5

5

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 butter

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–280

ENGINE DRIVEABILITY AND EMISSIONS

Backfire Symptom

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Fuel ignites in the intake manifold, or in the exhaust
system, making a loud popping noise.

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

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?

—

Verify repair

Go to 

Step 3

3

Was a visual/physical check performed?

—

Go to 

Step 4

Go to

Visual/Physic

al Check

4

1. Check for proper ignition voltage coil output with

spark tester 5-8840-0383-0.  Refer to 

Electric

Ignition System for procedure.

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

Was a problem found?

—

Verify repair

Go to 

Step 5

5

1. Remove spark plugs and 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. Refer to 

DTC P0172 to determine the

cause of a rich condition or 

Engine Mechanical for an oil

fouling condition.

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

Was a problem found?

—

Verify repair

Go to 

Step 6

6

1. Visually/physically inspect the ignition coils for

cracks.

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

Was a problem found?

—

Verify repair

Go to 

Step 7

7

1. Check for an intermittent ignition system

malfunction:

D

Intermittent CKP 58X signal.

D

Intermittent ignition feed circuit or sensor
ground circuit to the crankshaft position
sensor.

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

Was a problem found?

—

Verify repair

Go to 

Step 8

8

1. Check the fuel pressure.  Refer to 

Fuel System

Pressure Test.

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

Was a problem found?

—

Verify repair

Go to 

Step 9

6E–281

ENGINE DRIVEABILITY AND EMISSIONS

Backfire Symptom

  (Cont'd)

Step

No

Yes

Value(s)

Action

9

1. Check for the following engine mechanical

conditions.

Refer to 

Engine Mechanical for diagnosis

procedures:

D

Low compression

D

Sticking or leaking valves

D

Worn camshaft lobe(s)

D

Camshaft drive belt slipped or stripped

D

Incorrect valve timing

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

Was a problem found?

—

Verify repair

Go to 

Step 10

10

1. Check the intake and exhaust manifold(s) for

casting flash.  Refer to 

Engine Mechanical.

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

Was a problem found?

—

Verify repair

Go to 

Step 11

11

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 butter

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