Oxygen Sensor Heating Circuit Power Supply, Checking

Heated Oxygen Sensor (HO2S) heating circuit power supply, checking

- Disconnect Heated Oxygen Sensor (HO2S) harness connector at right engine mount.




- Connect VAG 1527B voltage tester to harness connector using cables from VW 1594 adapter kit.

- Start engine and let idle.
^ LED must light up

If NOT:
- Repair short/open circuit using wiring diagram.