Oxygen Sensor (O2S) 1 (Behind Three Way Catalytic Converter (TWC)) Heater Z29 , Checking

Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater Z29 , Checking

Special tools, testers and auxiliary items required
- Multimeter V.A.G 1526 or equivalent.
- Test Box 105 Pin VAG1598/42.
- Adapter Lead Vag1598/39 VAG1598/39.
- Adapter cable V.A.G 1598/39-1.

NOTE: When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 , use only gold-plated terminals.

Test requirements
- Fuse for Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.







Test sequence







- Disconnect the 4-pin electrical harness connector - 1 - from the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130.
- Using the Multimeter V.A.G 1526 A or equivalent, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminals 1 to 2 for resistance.
Specified resistance: 1.0 to 20.0 Ohms (at approx. 20 degrees C)

If the specified value is not obtained:
- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130.

If the specified value is obtained:
- Connect the Test Box 105 Pin VAG1598/42 to the wiring harness of the Engine Control Module (ECM) J623. The ECM is not connected.







- Using the Test Box 105 Pin VAG1598/42 and Multimeter V.A.G 1526 A or equivalent, check the following wiring connections for an open circuit.

Harness connector Terminal Test box Socket
2 7
3 76
4 77

Specified resistance 1.5 Ohms max.

If the specification is not obtained:
- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
- If necessary, repair the wiring connection.

If no malfunctions are found in wiring:
- Replace the Engine Control Module (ECM) J623.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

- End diagnosis and switch the ignition off.