Heater For Oxygen Sensors After Catalytic Converter, Checking
Heater for Oxygen Sensors after Catalytic Converter, Checking
Component location => [ Heater for Oxygen Sensor before Catalytic Converter, Checking ].
Oxygen sensor signals are monitored via On Board Diagnostic (OBD).
- Check DTC memory. If an oxygen sensor malfunction relating to heating circuit is displayed.
- Disconnect respective harness connector for oxygen sensor (connector strip bolted to underside of transmission).
2 4-pin harness connector for Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) and Oxygen Sensor (O2S) Heater 1 (Z29) behind catalytic converter, bank 1
3 4-pin harness connector for Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) and Oxygen Sensor (O2S) Heater 2 (Z30) behind catalytic converter, bank 2
- Perform continuity test (resistance measurement) between terminals 1 and 2 of respective sensor connector using portable multimeter (VAG1526).
Specified value at room temperature: 1 to 20 ohms
• At higher temperatures, resistance climbs sharply.
If specified value is not reached, replace respective Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130)/Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131).
If the specified value is obtained, check voltage supply of oxygen sensor.
Voltage Supply, Checking
• The respective fuses of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) and Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) must be OK:
• At certain operating points, the ECM "pulses" the Ground (GND) for oxygen sensor heating. This means that the Ground (GND) is constantly switched on and off at these operating points. It is therefore possible that the voltage displayed on the portable multimeter (VAG1526) will fluctuate.
- Connect portable multimeter (VAG1526) between terminal 1 (B+) and terminal 2 Ground (GND) of respective oxygen sensor connector.
- Operate starter briefly.(Do not let engine run longer than 2 minutes, because of malfunction entry)
Specified value: approx. battery voltage
If specified value is not obtained.
- Connect portable multimeter (VAG1526) between terminal 1 (B+) of respective oxygen sensor connector and engine Ground (GND).
- Operate starter briefly.(Do not let engine run longer than 2 minutes, because of malfunction entry)
Specified value: approx. battery voltage
If specified value is again not obtained.
- Check wire connection from terminal 1 of the respective oxygen sensor connector via fuse to Fuel Pump (FP) Relay (J17) for open circuit or short circuit.
- If voltage supply is OK, check wire connection.
Ground Wire Connections, Checking
- Check respective wire connection.
Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130), bank 1, with Oxygen Sensor (O2S) Heater 1 (Z29).
Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131), bank 2, with Oxygen Sensor (O2S) Heater 2 (Z30).
- Operate starter briefly. (Do not let engine run longer than 2 minutes, because of malfunction entry)
Specified value: approx. battery voltage
- Switch ignition off.
If specified value is not obtained, check wire connection.
Wire Connections, Checking
- Connect test box (VAG1598/31) to wiring harness of Engine Control Module (ECM).
- Check the following wire connections for open circuit.
Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130), bank 1, with Oxygen Sensor (O2S) Heater 1 (Z29).
Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131), bank 2, with Oxygen Sensor (O2S) Heater 2 (Z30).
- Repair open circuit in wiring or short circuit if necessary.
- If wire connection is OK but there is no Ground (GND) activation present for oxygen sensor heater, replace Engine Control Module (ECM), refer to Repair Manual and generate readiness code again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.