Oxygen Sensor Heater For Oxygen Sensor Behind Three Way Catalytic Converter (TWC) Checking

Oxygen sensor heater for oxygen sensors behind Three Way Catalytic Converter (TWC), checking

Note: When servicing terminals in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.

Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test requirements

- The respective fuses of Heated Oxygen Sensor (HO2S) -G130- must be OK.
- Ignition switched off.

- Disconnect 4-pin harness connector (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130- (-1-).

- Set multimeter for resistance measurement and connect it to terminals 1 & 2 at connector for oxygen sensor. Check oxygen sensor heater for continuity.

Specified value: 0 to 20 Ohms

If an open circuit is found in the oxygen sensor heater:

- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.

If oxygen sensor heater has continuity:

- Check voltage supply and wiring.

Checking voltage supply and wiring

- Set multimeter for voltage measurement and connect it to terminals 1 & 2 at connector to control module.

- Start engine, and let run at idle.

- Measure voltage supply

Specified value: oscillating between 0.0 and 12.0 V

If there is no voltage:

- Connect multimeter to terminal 1 of connector and engine Ground (GND) for voltage measurement.

Specified value: 11 to 15 V

If there is no voltage again:

- Check wire connection from terminal 1 to Fuel Pump (FP) Relay -J17- according to wiring diagram.

If voltage was approximately same as battery voltage:

- Switch ignition off.

- Connect test box to control module wiring harness.

Engine Control Module (ECM) is not connected.

- Check wire between test box and 4-pin connector for open circuit according to wiring diagram.

Terminal 2 & socket 63

Wire resistance: max: 1.5 Ohms

If no wiring faults are found:

- Replace Engine Control Module (ECM).