Oxygen Sensor (O2S) Heater Z19 For Heated Oxygen Sensor (HO2S) G39 Before Catalytic Converter, Checking

Oxygen Sensor (O2S) Heater Z19 For Heated Oxygen Sensor (HO2S) G39 Before Catalytic Converter, 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 Heated Oxygen Sensor (HO2S) G39 , use only gold-plated terminals.

Test requirements
- Fuse for Heated Oxygen Sensor (HO2S) G39 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 electrical harness connector - 2 - from the Heated Oxygen Sensor (HO2S) -G39-.
- Using Multimeter V.A.G 1526 A or equivalent, check the Heated Oxygen Sensor (HO2S) G39 electrical connector terminals 3+4 for resistance.
Specified value: 2.5 to 10.0 Ohms (at approx. 20 degrees C)

If the specified value is not obtained:
- Replace Heated Oxygen Sensor (HO2S) G39.

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
1 60
2 61
3 51
5 81
6 82

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.