With Generic Scan Tool
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
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 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 like, for example, lights and rear window heating must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- If 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 degree C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values
- Oxygen sensor heater for oxygen sensors behind catalytic converter must be OK. Oxygen Sensor (O2S) Heating -Z29- For After TWC, Checking
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
- Check the specified values of the output of oxygen sensor signals at idle:
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
- Disconnect 4-pin harness connector to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
- Use adapter cables from VAG1594 to connect multimeter to terminals 3 + 4 (Motronic ECM connector) for voltage measurement.
- 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. Readiness Code, Generating
If specified value is obtained:
- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
Checking oxygen sensor wires
- Check wires between test box and 4-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Wire resistance: max: 1.5 Ohm
Continuation for all vehicles
- Also check wires for short circuit to B+ and Ground (GND).
Specified value: Infinite Ohm
If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.