Oxygen Sensor and Oxygen Sensor Control Behind Three Way Catalytic Converter (TWC), Checking
Oxygen Sensor And Oxygen Sensor Control Behind Three Way Catalytic Converter (TWC), Checking
NOTE: When servicing terminals in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.
Recommended special tools and equipment
- V.A.G 1526 portable multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram
Test requirements
- The respective fuses of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- must be OK:
- Battery voltage must be at least 11.5 volts.
- All electrical consumers such as, lights and rear window heating must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- vehicle is equipped with an A/C system, it must be switched off.
- Ground (GND) connections between engine and chassis must be OK.
- Exhaust system must be properly sealed between catalytic converter and cylinder head.
- Coolant temperature must be at least 80 degrees C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measuring Values
- Oxygen sensor heater for oxygen sensors behind catalytic converter must be OK, check.
Function test
- Select the following output of oxygen sensor signals and check whether the specified values are being reached, Diagnostic mode 5: Check output of oxygen sensor signals. Diagnostic Mode 5: Check Output of Oxygen Sensor Signals
If specified values are obtained:
- End diagnosis and switch ignition off.
If specified values are not obtained:
- End diagnosis and let engine continue to run at idle.
- Check primary voltage
Checking primary voltage
Vehicles with engine code AEB
- Disconnect 4-pin harness connector (black) to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- (-1-).
- Use adapter cables from (VAG1594) to connect multimeter to terminals 3 + 4 (Motronic ECM connector) for voltage measurement.
Vehicles with engine code ATW
- Disconnect 4-pin harness connector (brown) to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- (-1-).
- Use adapter cables from VAG1594 to connect multimeter to terminals 3 + 4 (Motronic ECM connector) for voltage measurement.
Continued for all vehicles
- Start engine and measure primary voltage.
Specified value: 0.40 to 0.50 Volts
- Switch ignition off.
If specified value is not obtained:
- Test oxygen sensor wires.
- 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:
- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
Checking oxygen sensor wires
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
Vehicles with engine code AEB
- Disconnect 4-pin harness connector (black) to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- (-1-).
- Check wires between test box and 4-pin connector (to control module) for open circuit according to wiring diagram.
Terminal 3 + socket 51
Terminal 4 + socket 52
Wire resistance: max: 1.5 ohms
Vehicles with engine code ATW
- Disconnect 4-pin harness connector (brown) to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- (-1-).
- Check wires between test box and 4-pin connector (to control module) for open circuit according to wiring diagram.
Terminal 3 + socket 68
Terminal 4 + socket 69
Wire resistance: max: 1.5 ohms
Continued for all vehicles
- Check wires for short circuit to B+ and Ground (GND).
Specified value: Infinite ohms
If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.