Oxygen Sensor Heater For O2 Sensor After TWC, Checking

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

NOTE:
- Vehicle must be raised before connector for oxygen sensor is accessible.
- When servicing terminals 3 and 4 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.

Test sequence







- Unscrew protective cover (arrows) and disconnect 4-pin harness connector (brown) -1- to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.

Vehicles with engine code AEG, AVH, AZG







- Check resistance for sensor heater at connector to oxygen sensor terminal 1 + 2. Specified value: 1.0...5.0 Ohms (at room temperature)

Vehicles with engine code BDC

- Check resistance for sensor heater at connector to oxygen sensor terminal 1 + 2. Specified value: 8.0...20.0 Ohms (at room temperature)

Continuation for all vehicles

If specified value is not obtained:
- Replace Oxygen Sensor (O2S) 2 Bank 1 Behind Three Way Catalytic Converter (TWC) -G130-.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:
- Check Ground (GND) activation of oxygen sensor heater.
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AEG







- Check wires between test box and 4-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram. Terminal 2 + socket 28: Wire resistance: max. 1.5 Ohms

Vehicles with engine code AVH, AZG, BDC







- Check wires between test box and 4-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram. Terminal 2 + socket 63: Wire resistance: max. 1.5 Ohms

Continuation for all vehicles

- Also check wires for short circuit to B+ and Ground (GND): Specified value: Infinite Ohms
- Check wire between 4-pin connector terminal 1 and Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram: Wire resistance: max. 1.5 Ohms

If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.