P0103

DIAGNOSTIC TROUBLE CODES P0102, P0103
Mass air flow sensor, input to control module low/high, no continuity or shorting to ground/batt+.

Fault Symptoms
Reluctance to start, poorer driveablity and high fuel consumption.
The diagnostic trouble codes usually occur together with other trouble codes.
CHECK ENGINE lamp on.

Condition
Air flow less than 0.45 grams per second at engine speeds up to 1000 rpm, or
Air flow greater than 110 grams per second at engine speeds above 3600 rpm and engine temperature above 75°C (168°F).

NOTE: If the mass air flow sensor becomes inoperative, the control module will obtain information from the throttle position sensor instead.

Diagnostic Procedure.
1. With the ISAT command "AIR MASS" in the "OBTAIN READOUTS" menu, check that the following readings can be obtained on the display:
- approx. 4 gram/s on idling
- approx. 8 gram/s at 2500 rpm (no load)
- approx. 60 gram/s at full throttle (no load)

If the readings are correct, proceed to step 7.
If they are not, continue at step 2.

2. Check the induction system for leakage. Also inspect the large 0-ring between the air collector (resonator/silencer) and the throttle body.

3. Check that pin 1 of the mass air flow sensor is properly grounded.

If it is not, check the lead between pin 1 and grounding step G7P.





4. With the ignition switch in the DRIVE position, check that battery voltage is present on pin 3 of the mass air flow sensor.

If it is not, check the lead between pin 3 and pin 87 of the main relay.

5. With the ignition switch in the DRIVE position, check that pin 2 of the mass air flow sensor is properly grounded.

If it is not, check the lead between pin 2 and pin 26 of the control module.

6. With the ignition switched OFF, connect a BOB between the control module and the wiring.
Start the engine and check that current is present on pin 7 of the mass air flow sensor, as follows:
- approx. 1.0 V when idling
- approx. 1.5 V at 2500 rpm (no load)
- approx. 3.2 V at full throttle (no load)

7. If no fault has been detected after carrying out the above checking procedure, clear any diagnostic trouble codes, drive the car on the road and check whether the trouble code is generated afresh.

If it is, change the mass air flow sensor.

8. If the fault still persists, continue at "Before Control Module Replacement" for further diagnostic instructions. Before Replacing A Control Module