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

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

NOTE:
- Vehicle must be raised before connector for oxygen sensor is accessible.
- When servicing oxygen sensor terminals in harness connector, use only gold-plated terminals.

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Requirements







- The respective fuses of Heated Oxygen Sensor (HO2S) -G39- must be OK.
- Ignition switched off.

Work sequence (Vehicles with engine code AVH, AZG, BDC, BEV, BCD)







- Remove protective cover (arrows) and disconnect 6-pin harness connector (black) -1- to Heated Oxygen Sensor (HO2S) G39- before catalytic converter.







- Check resistance for sensor heater at connector to oxygen sensor terminal 3+4.

Specified value: 2.5 to 10.0 Ohms (at room temperature)

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







- Check wires between test box and 6-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.

Terminal 4 + socket 5

Wire resistance: max. 1.5 Ohms

- Check wires for short circuit to B+ and to Ground (GND).

Specified value: Infinite Ohms

- Check wire between 6-pin connector terminal 3 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-.