Heated Oxygen Sensor (HO2S) G39 and Oxygen Sensor Regulation Before Catalytic Converter, Checking

Heated Oxygen Sensor (HO2S) G39 And Oxygen Sensor Regulation 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.
- Oxygen Sensor (O2S) Heater Z19 before catalytic converter OK, checking. Oxygen Sensor (O2S) Heater Z19 For Heated Oxygen Sensor (HO2S) G39 Before Catalytic Converter, Checking
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Exhaust system between catalytic converter and cylinder head properly sealed.
- Coolant Temperature at least 80 degrees C.

Function test
- Connect the diagnostic tester.
- Start engine and let it run at idle.
- Select "Diagnostic mode 6: Check test results of components that are not continuously monitored".
- Select "Test-ID 01: Oxygen sensor monitoring before catalytic converter".
- Select "Test-ID 131: Dynamic test" and check whether specified values are obtained.







- End diagnosis and switch ignition off.

If specified values are not obtained:
- Check Heated Oxygen Sensor (HO2S) G39 wiring.

Testing of oxygen sensor wires







- Disconnect the 6-pin electrical harness connector - 2 - from the Heated Oxygen Sensor (HO2S) -G39-.
- 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.

Terminal Test box socket
1 60
2 61
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 Heated Oxygen Sensor (HO2S) -G39-.

Final procedures
After repair work, the following work steps must be performed in the following 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 ignition off.