Electrical Testing

SENSOR ELECTRICAL TESTS:

NOTE:
- G39 = Heated Oxygen Sensor (HO2S), bank 1.
- G108 = Heated Oxygen Sensor (HO2S) 2, bank 2.

- Disconnect Heated Oxygen Sensors (HO2S) -G39- or -G108- harness connector.



- Switch multimeter (Fluke 83 or equivalent) to resistance measuring range and and check for continuity between terminal 4 oxygen sensor signal wire (measured at oxygen sensor connector) and engine Ground (GND).

If continuity is not obtained:
- Replace heated oxygen sensor.

If continuity obtained:



- Switch multimeter (Fluke 83 or equivalent) to 2 volt range and connect between terminal 4 on harness connector and engine Ground (GND).

- Switch ignition ON.

Specified Value: 400 ± 50 mV.

If the specified value is not obtained, check wiring to ECM as follows:
- Switch ignition OFF.
- Connect VAG 1598/19 test box to ECM harness connector.
- Check wiring for continuity between terminal 4 (HO2S -G39-) and terminal 20 on ECM connector A.

Specified Value: max. 1 Ohms.

- Check wiring for continuity between terminal 4 (HO2S 2 -G108-) and terminal 21 on ECM connector A.

Specified value: max. 1 Ohms.

If the specified Value is not obtained:



- Eliminate open or short Circuit using wiring diagram.

If wiring OK:
- Replace ECM .