Oxygen sensor heating, checking
Only vehicles with engine code BEW
NOTE:
- Vehicle must be raised before connector for oxygen sensor is accessible.
- When servicing terminals in harness connector of oxygen sensor, use only gold-plated terminals.
Recommended special tools and equipment
- V.A.G1526 multimeter or V.A.G1715 multimeter
- V.A.G1594 connector test kit
- Wiring diagram
Test requirements
- The respective fuses of Diesel-Direct fuel injection system must be OK:
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations
- Ignition switched off.
- Disconnect 6-pin harness connector to Heated Oxygen Sensor (HO2S) -G39-. Harness connector of oxygen sensor is located at vehicle floor under a synthetic cover.
- Check resistance for sensor heater at connector to oxygen sensor terminal 3 + 4.
Specified value: 2.5 to 4.4 Ω (at room temperature)
If specified value is not obtained:
- Replace Heated Oxygen Sensor (HO2S) -G39-. Refer to item 8 in Front exhaust pipe and catalytic converter with attachments (vehicles with engine code BEW) .
- Erase DTC memory of control module for Diesel-Direct fuel injection system. Refer to Diagnostic mode 4: Reset/erase diagnostic data .
- Generate readiness code.
If specified value is obtained:
- Check Ground (GND) activation of oxygen sensor heater.
- Connect test box to control module wiring harness. Refer to Test box, connecting for wiring test .
- Connect adapter cable (V.A.G 1598/39-2) to test box (V.A.G 1598/42).
- Check wires between test box and 6-pin connector (to control module for Diesel-Direct fuel injection system) for open circuit according to wiring diagram.
Terminal 3 + socket 51
Wire resistance: max. 1.5 Ω
- Check wires for short circuit to B+ or Ground (GND).
Specified value: ∞ Ω
If no malfunctions are found in wires:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to Control module for Diesel-Direct Fuel Injection System, replacing .
- Generate readiness code.