Content .. 1496 1497 1498 1499 ..

Opel Frontera UE. Manual - part 1498

6E–207

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0300 – Engine Misfire Detected

(Cont'd)

Step

Yes

Value(s)

Action

1. Install a spark tester at the spark plug end of the

ignition coil for a cylinder that indicated a misfire.

2. Crank the engine while observing the spark tester.

A crisp, blue spark should be observed.

Is adequate spark present?

—

Go to

Step 14

Go to

Step 9

1. Remove and visually/physically inspect the ignition

coil(s) associated with the cylinders that were
indicated as misfiring. Ensure that the coil(s) are
free of cracks.

2. If a problem is found, replace the damaged ignition

coil(s) as necessary.

Did any ignition coils require replacement?

—

Verify repair

Go to

Step 10

1. Remove the spark plugs from the cylinders that

were indicated as misfiring.

2. Visually inspect the spark plug electrodes.

Does your inspection reveal any spark plugs exhibiting
excessive fouling?

—

Go to

Engine

Mechanical

Diagnosis

Go to

Step 11

1. Visually inspect the spark plug insulators for cracks,

carbon tracking, or other damage.

2. If a problem is found, replace the faulty spark

plug(s) as necessary.

Did your inspection reveal a problem?

—

Verify repair

Go to

Step 12

1. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in “closed loop” while

monitoring the “BANK 1 L.T. FUEL TRIM” and
“BANK 1 S.T. FUEL TRIM” display on the Tech 2.

Do both values decrease below the specified values?

”BANK 1 L.T.

FUEL TRIM”

below +20%;

“BANK 1 S.T.

FUEL TRIM”

below +50%

Go to

Step 13

Replace the

ignition coil of

the affected

cylinder

Replace the ignition coil control module.

Is the action complete?

—

Verify repair

—

1. Visually and physically inspect the PCM injector

grounds, power grounds and sensor grounds to
ensure that they are clean, tight and in their proper
locations.

2. If a problem is found, correct the faulty ground

condition as necessary.

Did your inspection reveal a poor ground?

—

Verify repair

Go to

Step 15

1. Perform the “Fuel System Pressure Test”

procedure.

2. If a problem is found, repair as necessary (refer to

Engine Fuel or Fuel Metering System).

Was a fuel system problem found?

—

Verify repair

Go to

Step 16

1. Check the fuel for excessive water, alcohol, or other

contaminants (refer to

Diagnosis in Engine Fuel for

procedure).

2. If a problem is found, correct the contaminated fuel

condition as necessary.

Was the fuel contaminated?

—

Verify repair

Go to

Step 17

SECTION

6E–208

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0300 – Engine Misfire Detected

(Cont'd)

Step

Yes

Value(s)

Action

1. Perform the “Injector Coil/Balance Test”.
2. If a problem is found, replace faulty injector(s) as

necessary.

Did any of the injectors require replacement?

—

Verify repair

Go to

Step 18

1. Check for an engine mechanical problem. Refer to

Engine Mechanical Diagnosis to diagnose the
following conditions:

A faulty or incorrect camshaft

Leaking or sticky valves or rings

Excessive valve deposits

Weak valve springs

Incorrect valve timing

A leaking head gasket

A loose or broken motor mount

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

Was a basic engine mechanical problem found and
repaired?

—

Verify repair

Go to

Step 19

1. Check for a transmission TCC problem. Refer to

4L30-E Automatic Transmission Diagnosis.

2. If a problem is found, repair the transmission as

necessary. Refer to

4L30-E Automatic

Transmission Unit Repair.

Was a transmission problem found and repaired?

—

Verify repair

Go to

Step 20

Replace the MAF sensor.

Is the action complete?

—

Verify repair

—

SECTION

6E–209

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0301 Cylinder Misfire Detected

Circuit Description

Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
This DTC P0301 will determine if the No.1 cylinder misfire
is occurring by monitoring the Combustion Quality.

Conditions for Setting the DTC

None of the following DTCs occur: TP sensor, MAF
sensor, vehicle speed sensor, ECT sensor.

The engine speed is between 600 and 6250 RPM.

The system voltage is between 11 and 16 volts.

The ECT indicates an engine temperature between
–7

C (28

F) and 110

C (230

F).

The throttle angle is steady and throttle change less
than 0.4% per 125 milliseconds.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive ignition cycle in which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0301 will clear after 40 consecutive
ignition cycles occur without a fault.

DTC P0301 can be cleared by using the Tech 2 “Clear
Info” function.

Diagnostic Aids

Check for the following conditions:

System grounds – Ensure all connections are clean
and properly tightened.

Injector – Perform the injector coil/balance test to
locate a faulty injector that contributes to a lean
condition on the affected cylinder. In addition to the
above test, check the condition of the injector O-ring.

Faulty spark plug – Check for a cracked insulator,
carbon tracking, incorrect gap, and worn electrodes.

Damaged or faulty ignition coil – Check for cracks or
other damage.

Substitute a known good coil – Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.

DTC P0301 – Cylinder Misfire Detected

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Start the engine. Run the engine at idle.
2. Review and record Tech 2 Freeze Frame data.
3. Monitor “Misfire Cur. #1” on the Tech 2.

Is “Misfire Cur. #1” increasing (indicating a misfire
currently occurring)?

—

Go to

Step 4

Go to

Step 3

Monitor “Misfire Hist. #1” while operating the vehicle to
duplicate the conditions present when the DTC was set
(as defined by the Freeze Frame data recorded in Step
2).

Is “Misfire Hist. #1” increasing (indicating a misfire
currently occurring)?

—

Go to

Step 4

Refer to

Diagnostic

Aids

1. Visually and physically inspect the vacuum hoses

for splits, kinks, and improper connections. Also,
inspect the intake manifold for a vacuum leak.

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

Did the inspection reveal a problem?

—

Verify repair

Go to

Step 5

1. Install a spark tester at the spark plug end of the

cylinder #1 ignition coil.

2. Crank the engine while observing the spark tester.

A crisp, blue spark should be observed.

Is adequate spark present?

—

Go to

Step 8

Go to

Step 6

SECTION

6E–210

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0301 – Cylinder Misfire Detected

(Cont'd)

Step

Yes

Value(s)

Action

1. Remove and visually/physically inspect the ignition

coil associated with cylinder #1. Ensure that the coil
is free of cracks and carbon tracking.

2. If a problem is found, replace the damaged ignition

coil as necessary.

Did the visual inspection reveal a problem?

—

Verify repair

Go to

Step 7

1. Measure the ignition coil primary resistance.
2. If resistance is not within the specified value,

replace the faulty ignition coil.

Did the ignition coil require replacement?

2.6-2.7 K

Verify repair

Go to

Step 12

Remove the cylinder #1 spark plug and visually inspect
the spark plug electrode.

Does the inspection reveal excessive fouling?

—

Go to

Contaminatio

n Diagnosis

chart in

Engine

Mechanical

Diagnosis

Go to

Step 9

1. Visually inspect the spark plug insulator for cracks,

carbon tracking, or other damage.

2. If the spark plug is damaged, replace the spark plug.

Did the inspection reveal a problem?

—

Verify repair

Go to

Step 10

1. Perform the “Injector Coil/Balance Test”.
2. If any faulty injectors are found, replace them as

necessary.

Did any of the injectors require replacement?

—

Verify repair

Go to

Step 11

1. Inspect the injector O-rings for a vacuum leak.
2. If a problem is found, repair it as necessary.

Did the inspection reveal a problem?

—

Verify repair

Go to

Step 12

Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose and repair
the following conditions:

A faulty or incorrect camshaft

Leaking or sticky valves or rings

Excessive valve deposits

Weak valve springs

A leaking head gasket

Was a basic engine mechanical problem found?

—

Verify repair

Refer to

Diagnostic

Aids

SECTION

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