With Generic Scan Tool

Oxygen Sensor (O2S) Heater 1 -Z29- Behind Catalytic Converter, Checking







Recommended special tools and equipment
- V.A.G1526A hand multimeter
- V.A.G1594A connector test kit
- V.A.G1598/31 test box

Test requirements:
- Fuse for oxygen sensor heater OK
- Ground (GND) connections at engine and transmission OK
- Fuel Pump (FP) Relay OK; checking.
- Ignition switched off.

NOTE:
- Voltage is supplied to Oxygen Sensor (O2S) Heater 1 -Z29- via the Fuel Pump (FP) relay.
- When servicing terminals in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.

Procedure







- Disconnect 4-pin harness connector -2- (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) - G130-.

NOTE:







Coolant reservoir screw (arrow) must be removed and coolant reservoir must be placed to the side in order to access harness connector. The coolant hoses remain connected.

Checking internal resistance







- Connect multimeter between terminal 1 and 2 for resistance measurement.

Specified value at room temperature: 6.4 to 47.5 Ohms

If specified value is not obtained:
- Replace oxygen sensor behind catalytic converter.

If specified value is obtained:

Checking voltage supply







- Connect multimeter between terminal 1 and 2 for voltage measurement.
- Operate starter briefly.

Specified value: approx. battery voltage

If there is no voltage:
- Connect multimeter for voltage measurement as follows:

Harness connector Terminal Measure to
1 Engine Ground (GND)

- Operate starter briefly.

Specified value: approx. battery voltage

- Switch ignition off.

If there is no voltage again:
- Check wire connection from harness connector terminal 1 to Fuel Pump (FP) Relay -J17- via fuse for open circuit according to wiring diagram.

Specified value: Wire resistance max 1.5 Ohms

- If necessary, repair wire connection.

If voltage supply is OK:

Check Ground (GND) activation







- Connect multimeter for voltage measurement as follows:

Harness connector Terminal Measure to
2 B+

- Operate starter briefly.

Specified value: approx. battery voltage, possibly fluctuating

- Switch ignition off.

If specified value is not obtained:
- Connect test box to wiring harness of Engine Control Module (ECM). ECM is not connected.







- Check the following wire connections for open circuit according to wiring diagram:

Harness connector Terminal Test box Socket
2 63

Specified value: Wire resistance max 1.5 Ohms

- Check wires for short circuit to B+ and Ground (GND).

Specified value: & (no continuity)

- If necessary, repair wire connection.

If no malfunctions are detected:
- Replace Engine Control Module (ECM).

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory, see"Mode 3: Check DTC memory"
2. If necessary, erase DTC memory See "Mode 4: Reset/erase diagnostic data"
3. Generate readiness code With Generic Scan Tool

- End diagnosis and switch ignition off.