Air Flow Sensor Plate Position Sensor: Testing and Inspection

Air Flow Sensor Plate Potentiometer Location:

1. With the ignition "OFF" detach the air flow sensor potentiometer harness connector.

Air Flow Sensor Plate Test Connection:

2. Install test harness V.A.G. 1501 or equivalent at the air flow sensor plate potentiometer electrical plug. Reconnect the injection harness to the test harness.
3. With the volt meter connected between terminal 1 and 3 of the test harness switch the ignition "ON".

^ The correct measurement should be 4.35 to 5.35 VDC.

If the correct measurement is not obtained, the wiring harness or the Motronic control unit is defective.


4. With the ignition "OFF", connect the volt meter between terminals 2 and 3 of the test harness.
5. Start the engine and run at idle for approx. 2 minutes.

Potentiometer Voltage Chart:

6. Refer to the result from test step 3 and compare the measured voltage to the Voltage Graph. If the voltage is not within specifications, check for possible air leaks. If no air leaks are present, the potentiometer can be adjusted. Refer to ADJUSTMENT PROCEDURES.

^ If the potentiometer cannot be adjusted with the trim screw to obtained the correct specification, and there are no vacuum leaks present, the air flow sensor assembly (complete) should be replaced.