Camshaft Position Sensor: Testing and Inspection

CHECKING BATTERY POSITIVE VOLTAGE (B+) SUPPLY
- Disconnect Camshaft Position (CMP) sensor harness connector.
- Switch multimeter (Fluke 83 or equivalent) to 20 volt DC range.

3 Pin Harness Connector:

- Connect multimeter (Fluke 83 or equivalent) between terminals 1 (positive) and 3 (GND) of the CMP harness connector.
- Switch ignition ON.
^ Specified value: minimum 9 volts

If the specified value is not obtained:
- Check wiring between CMP sensor and the Engine Control Module (ECM).

If the specified value is obtained:
- Check function of the CMP.

If the specified value is not obtained and the wiring tests OK:
- Replace the ECM.

CHECKING FUNCTION OF CMP SENSOR
- Reconnect CMP harness connector.
- Push back rubber boot on CMP connector and connect LED tester (VAG 1527B or equivalent) to terminals 2 and 3.
- Operate starter a few seconds.
^ LED tester must blink briefly (every 2nd engine revolution).

If the LED tester does not blink:
- Check wiring between CMP sensor and the Engine Control Module (ECM).

If the wiring is OK and power and grounds test OK:
- Replace the CMP sensor.

CHECKING WIRING BETWEEN CMP SENSOR AND THE ECM
- Connect VAG 1598/19 test box to ECM. Refer to Computer and Control Systems, System Diagnosis, VAG 1598 Pin Out Box Connecting. Connecting VAG 1598/31 Test Box
- Disconnect Camshaft Position (CMP) sensor harness connector.
- Check for continuity from terminal 1 of CMP connector to test box socket A 2.
^ Specified value: maximum 1.0 ohm
- Check for continuity from terminal 2 of CMP connector to test box socket B 9.
^ Specified value: maximum 1.0 ohm
- Check for continuity from terminal 3 of CMP connector to test box socket D 12.
^ Specified value: maximum 1.0 ohm

If specified value is not obtained:
- Repair break in wiring and/or short between CMP sensor connector and ECM connectors.