With Generic Scan Tool
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 terminals in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.
Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram
Test requirements
- The respective fuses of Heated Oxygen Sensor (HO2S) -G39- must be OK.
- Ignition switched off.
Test sequence
- Unscrew 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...10.0 Ohm (at room temperature)
If specified value is not obtained:
- Replace Heated Oxygen Sensor (HO2S) -G39- bank 1 before catalytic converter:
- Vehicles with engine code AFP, item 7.
- Vehicles with engine code BDF, item 11.
- 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 Ohm
- Also check wires for short circuit to B+ and Ground (GND).
Specified value: infinite Ohm
- 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 Ohm
If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.