DTC 2232

1. With the ignition "OFF", disconnect the Motronic control unit harness connector. The Motronic control unit is located beneath the drip tray, at the left rear (drivers side) of the engine compartment.
2. Connect a suitable volt/ohm meter between terminal 23 and 26 of the Motronic control unit harness connector. Set the volt/ohm meter to ohms.

Special Tools:

CAUTION: Avoid damaging the delicate connectors within the control unit harness connector. A simple set of test leads can be fabricated using flat connectors (part # VW N 17 457 2) or equivalent, and a pair of alligator clips.

3. Verify that the air flow sensor plate is in its normal rest position. Remove the intake air boot and do a visual inspection. Refer to FUEL SYSTEMS for specifications and adjustment procedures, if necessary.

^ The correct measurement should be approx. 4500 to 5500 ohms.

4. Repeat steps 2 and 3, however with the ohmmeter connected between terminal 26 and 35 of the Motronic harness connector.

^ The correct measurement should be approx. 3800 to 4200 ohms.

5. If the correct measurements are obtained continue with step 6. If the correct measurements are not obtained, disconnect the air flow sensor plate potentiometer electrical connector and check for continuity between terminal:

a. 26 of the control unit and terminal 1 of the air flow sensor plate potentiometer.
b. 23 of the control unit and terminal 2 of the air flow sensor plate potentiometer.
c. 3 of the air flow sensor plate potentiometer and ground.

^ The correct measurement should be less than 1 ohm on all circuits.

If the correct measurements are not obtained repair or replace the harness as necessary.
If the correct measurements are obtained, continue with step 6.

Air Flow Sensor Plate Test Connection:

6. With the ignition "OFF", reconnect the Motronic control unit harness to the control unit.
7. Install test harness V.A.G. 1501 or equivalent at the air flow sensor plate potentiometer electrical connection.
8. 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, replace the Motronic control unit.

If the correct measurement is obtained, continue with step 9.

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

Potentiometer Voltage Chart:

11. Compare the measured voltage to the Voltage Graph. If the voltage is not within specifications, 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.