Oxygen Sensor Regulation Behind Catalytic Converter, Checking
Diagnostic Procedures
Oxygen Sensor Regulation Behind Catalytic Converter, Checking
• Vehicle must be raised before the electrical connector for the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) is accessible.
• When servicing terminals 3 and 4 in the electrical harness connector of the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130), use only gold-plated terminals.
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) fuse OK.
• Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC) Heater ( G130) OK. Refer to the repair information.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, selector lever in position " P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Exhaust system between catalytic converter and cylinder head properly sealed.
• Coolant Temperature at least 80 °C.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check
• If an O2 sensor heater code is also set, perform the test for the O2 heater first.
Start diagnosis
- Connect scan tool.
- Start the engine and let it run at idle.
- Select "Diagnostic mode 6: Check test results of components that are not continuously monitored".
- Select "Test-ID 02: Oxygen sensor monitoring behind catalytic converter".
- Select following Test-IDs.
- Check the specified values at idle.
If the specified values were obtained:
- Switch ignition OFF. Fault is not active at this time. Check for poor connections, loose terminals and harness check.
If the specified values were Not obtained:
- Remove the right vehicle floor cover - arrows -.
Checking primary voltage
- Disconnect the brown Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) electrical harness connector - arrow -.
- Switch the ignition ON.
- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) electrical harness connector terminals 3 to 4 for voltage.
Specified value: 0.400 to 0.500 Volts
- Switch the ignition OFF.
If the specified value was obtained:
- Replace the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) ( G130) Refer to the repair information.
If the specified value was Not obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
- Install the test box.
If the manufacturers test box is not being used, perform the following step.
- Remove the Motronic Engine Control Module (ECM) ( J623). Refer to the repair information.
- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) ( G130) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical harness connector terminals for an open circuit according to the wiring diagram.
Specified value: 1.5 ohms Max.
If the specified value was Not obtained:
- Check the wiring for an open, high resistance or short to ground.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the repair information.
- Install the right vehicle floor cover - arrows -.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Scan Tool Testing and Procedures.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Scan Tool Testing and Procedures.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.