Oxygen Sensor and Regulation After Catalytic Converter, Checking
Oxygen Sensor and Regulation after 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 (Z29) OK. Refer to => [ Oxygen Sensor 1 Heater, Checking ] Oxygen Sensor 1 Heater, Checking.
• 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 -.
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 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. Refer to repair information.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) (J220). Refer to 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) (J220) 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 each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, lose 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) (J220). Refer to 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 ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.