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 oxygen sensor connector is accessible.
- When servicing terminals in harness connector of oxygen sensor, 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
Test requirements
- The respective fuses of Heated Oxygen Sensor (HO2S) -G39- must be OK.
- Fuel Pump (FP) Relay -J17- must be OK, check.
- Ground (GND) connections between engine and chassis must be OK.
- Ignition switched off.
Test sequence
- Remove protective cover (arrows) and disconnect 6-pin harness connector to Heated Oxygen Sensor (HO2S) -G39- before catalytic converter.
Checking resistance
- 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) 1 bank 1 -G39- before catalytic converter.
- 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.
Checking 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 APH, AWP, AWV
- 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 the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms
Vehicles with engine code BKF, BNU
- Check wires between test box and 6-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Terminal 3 + 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 4 and the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms
Continue for all vehicles
- 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 no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220.