P0102

MASS AIR FLOW SENSOR





Fault Symptom.
CHECK ENGINE lamp (MIL) on.
Engine reluctant to start and poor driveability.
High fuel consumption.
Lumpy idle.

Conditions.
P0102
Engine rpm < 1400 rpm and intake air mass < 0.45 g/s (open circuit/shorting to ground).
P0103
Engine rpm < 3600 rpm and intake air mass > 111 g/s.

Diagnostic Help.
The performance of the mass air flow sensor can be ascertained with an ISAT scan tool.

- Connect an ISAT scan tool.
- Start the engine.
- Select "READ FUNCTIONS".
- Select "MASS AIR FLOW SENSOR".

Check that the ISAT scan tool shows the following air mass as a function of engine rpm:

^ idling speed: about 1.0 V
^ at 2500 rpm: about 1.5 V

All electrical equipment disconnected and selector lever in position N.
Slightly higher values will be obtained with a cold engine.

Check The Wiring.
Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter, ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1 Check the control module's mass air flow sensor input
- Unplug the mass air flow sensor's 4-pin connector.
- Connect an ISAT scan tool.
- Turn the ignition switch to the ON position.
- Select "READ FUNCTIONS".
- Select "MASS AIR FLOW SENSOR".
The ISAT scan tool should show a reading of about 0.0 V (about 0.0 g/s).
- Connect a 1.5 V battery in good condition to pins 4 and 2 of tile connector.
The ISAT scan tool should show a reading of about 1.5 V (about 10 g/s).

Are both readings OK?

YES:
^ Continue with point 3.
NO:
^ Continue with point 2.





2 Check The Wiring between the control module and mass air flow sensor
- Check for continuity between:
^ pin 41 of the control module and pin 4 of the connector.
^ pin 14 of the control module and pin 2 of the connector.

The resistance reading obtained should be less than 1 ohm.

Is the wiring OK?

YES:
^ Continue with point 4.
NO:
^ Rectify the fault. Continue with point 4.

3 Check the mass air flow sensor 5 power supply and ground connections
- Check for continuity between:
^ pin 1 of the connector and grounding point G7P.
^ pin 3 of the connector and fuse 16B.

The resistance reading obtained should be less than 1 ohm.

Is the wiring OK?

YES:
^ Change the mass air flow sensor. Continue with point 4.
NO:
^ Rectify the fault. Continue with point 4.





4 Final check
- Clear the diagnostic trouble code,
- Implementation of driving cycle:
^ Drive the car at varying engine loads and rpm for 5 minutes.
- Evaluation of driving cycle:

Check whether the diagnostic trouble code has recurred.

Has the diagnostic trouble code recurred?

YES:
^ Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO:
^ The steps taken to rectify the fault were correct.