Oxygen Sensor O2S Behind Three Way Catalytic Converter, Checking

Oxygen Sensor O2S Behind Three Way Catalytic Converter, Checking

Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

• 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 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

• Generic scan tool

•

• multimeter.

• Wiring diagram.

Test requirements

• The Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) fuse Ok.





• Oxygen Sensor O2S Behind Three Way Catalytic Converter Heater (Z29) OK.

• 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 (GND) 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

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 are obtained:

- End diagnosis and switch ignition off.

If the specified values are not obtained:

- Remove the right vehicle floor cover - arrows -. Refer to the appropriate service manual.





Checking primary voltage

- Disconnect the 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 not obtained:

- Replace the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130). Refer to the appropriate service manual.

If the specified value was 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 appropriate service manual.

- 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 T94 terminals for an open circuit according to the wiring diagram.










Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for a short circuit to Battery (+), or an open circuit.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is found in the wiring:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the appropriate service manual.

- Install the right vehicle floor cover - arrows -. Refer to the appropriate service manual.





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 ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.