Opel Frontera UBS. Manual - part 1185

6E–106

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0101 – MAF System Performance

  (Cont'd)

Step

No

Yes

Value(s)

Action

6

1. Ignition “ON,” engine “OFF.”
2. Review the Freeze Frame and/or Failure Records

data for this DTC and note parameters.

3. Ignition “OFF” for 15 seconds.
4. Start the engine and operate the vehicle within the

conditions required for this diagnostic to run, and as
close to the conditions recorded in Freeze Frame
/Failure Records possible. (Special operating
conditions that need to be met before the PCM will
run this diagnostic (where applicable) are listed in
“Conditions for Setting the DTC”).

5. Using the Tech 2, select “DTC,”  then enter the DTC

number which was set.

Does the Tech 2 indicate that this diagnostic failed this
ignition?

—

Go to 

Step 7

Refer to

Diagnostic

Aids

7

1. Check for the following conditions:

D

Objects blocking  the MAF sensor inlet screen;

D

Intake manifold vacuum leaks;

D

Vacuum leaks at throttle body;

D

Vacuum leaks EGR value flange and pipes.

D

Crankcase ventilation valve faulty, missing, or
incorrectly installed.

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

Was a problem found?

—

Verify repair

Go to

Step 8

8

1. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine “OFF.”
4. Using DVM 5-8840-0285-0, measure voltage

between the MAF sensor signal circuit and chassis
ground.

Is the voltage near the specified value?

5 V

Go to 

Step 9

Go to

Step 10

9

Connect a test light (5-8840-0607-0) between the MAF
sensor ignition feed and ground circuits at the MAF
sensor harness connector.

Is the test light “ON?”

—

Go to 

Step 13

Go to

Step 12

10

Is the voltage less than the specified value?

4.5 V

Go to 

Step 13

Go to

Step 11

11

1. Ignition “OFF,” disconnect the PCM.
2. Ignition “ON,” engine “OFF.”
3. Measure voltage between the MAF signal circuit

and ground.

Does the voltage measure near the specified value?

0 V

Go to 

Step 13

Go to

Step 12

12

Connect a test light (5-8840-0607-0) between the MAF
sensor ignition feed circuit and chassis ground.

Is the test light “ON?”

—

Go to 

Step 13

Go to

Step 7

13

1. Check for a poor connection at the MAF sensor.
2. If a poor connection is found, replace faulty

terminal(s).  Refer to 

Repair Procedures in

Electrical Diagnosis (8A Cell 5).

Was a poor connection found?

—

Verify repair

Solved

6E–107

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0102 MAF Sensor Circuit  Low Frequency

T321122

Circuit Description

The mass air flow (MAF) sensor measures the amount of
air which passes through it into the engine during a given
time.  The powertrain control module (PCM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations.  A large quantity
of air entering the engine indicates an acceleration or high
load situation, while a small quantity of air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which can
be monitored using a Tech 2.  The frequency will vary
within a range of around 2500 Hz at idle to around
1900 Hz at maximum engine load.  DTC P0102 will be set
if the signal from the MAF sensor is below the possible
range of a normally operating MAF sensor.

Conditions for Setting the DTC

D

The engine is running above 500 RPM for greater than
10 seconds.

D

System voltage is above 11.5 volts.

D

MAF signal frequency is below 1000 Hz for a total of
50-percent of the last 1000 samples monitored.  A
sample is taken every cylinder event.

Action Taken When the DTC Sets

D

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

D

The PCM calculates an air flow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.

D

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

D

DTC P0102 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

D

Poor connection at PCM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

D

Misrouted harness – Inspect the MAF sensor harness
to ensure that it is not routed too close to high voltage
wires.

D

Damaged harness – Inspect the wiring harness for
damage.  If the harness appears to be OK, observe the
Tech 2 while moving connectors and wiring harnesses
related to the MAF sensor.  A change in the display will
indicate the location of the fault.

D

Plugged intake air duct or filter element – A wide-open
throttle acceleration from a stop should cause the
mass air flow displayed on a Tech 2 to increase from
about 3-6 g/second at idle to 100 g/second or greater
at the time of the 1-2 shift.  If not, check for a restriction.

If DTC P0102 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–108

ENGINE DRIVEABILITY AND EMISSIONS

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. This step verifies that the problem is present at idle.

4. A voltage reading of less than 4 or over 5 volts at the

MAF sensor signal circuit indicates a fault in the
wiring or a poor connection.

5. This verifies that ignition feed voltage and a good

ground are available at the MAF sensor.

DTC P0102 – MAF Sensor Circuit Low Frequency

 

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. Start the engine.
2. With the engine idling, monitor “MAF Frequency”

display on the Tech 2.

Is the “MAF Frequency” below the specified value?

3 g/Sec

Go to 

Step 4

Go to 

Step 5

3

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “DTC” info for DTC P0102.

Does the Tech 2 indicate DTC P0102 failed this
ignition?

—

Go to 

Step 4

Refer to

Diagnostic

Aids

4

1. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine “OFF.”
4. Using a DVM, measure voltage between the MAF

sensor signal circuit and battery ground.

Is the voltage near the specified value?

5 V

Go to 

Step 5

Go to 

Step 8

5

Connect a test light between the MAF sensor ignition
feed and ground circuits at the MAF sensor harness
connector.

Is the test light “ON?”

—

Go to 

Step 13

Go to 

Step 6

6

Connect a test light between the MAF sensor ignition
feed circuit and battery ground.

Is the test light “ON?”

—

Go to 

Step 12

Go to 

Step 7

7

1. Check for a poor connection at the MAF sensor.
2. If a poor connection is found, replace the faulty

terminal(s).

Was a poor connection found?

—

Verify repair

Go to 

Step 11

8

1. Ignition “OFF.”
2. Disconnect the MAF sensor.
3. Disconnect the PCM connector for the MAF signal

circuit.

4. Ignition “ON,” engine “OFF.”
5. With the DVM, measure the voltage between the

MAF signal terminal at the PCM and battery ground.

Is the voltage under the specified value?

4 V

Go to 

Step 9

Go to 

Step 10

6E–109

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0102 – MAF Sensor Circuit Low Frequency

  (Cont'd)

Step

No

Yes

Value(s)

Action

9

1. Ignition “OFF.”
2. Disconnect the PCM white connector.
3. Ignition “ON.”
4. Check the MAF sensor signal circuit for a short to 5

volts.

Is the action complete?

—

Verify repair

—

10

1. Ignition “OFF.”
2. Disconnect the PCM white connector.
3. Ignition “ON.”
4. Check the MAF sensor signal circuit between the

PCM and the MAF sensor for an open, short to
ground, or short to the MAF ground circuit.

Is the action complete?

—

Verify repair

Go to 

Step 13

11

Locate and repair the open in the ground circuit to the
MAF sensor.

Is the action complete?

—

Verify repair

—

12

Locate and repair the open in the ignition feed circuit to
the MAF sensor.

Is the action complete?

—

Verify repair

—

13

Replace the MAF sensor.

Is the action complete?

—

Verify repair

Go to 

Step 14

14

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed.  Refer to 

UBS 98model year Immobilizer

Workshop Manual.

Is the action complete?

—

Verify repair

—