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 And Workshop Equipment 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 appropriate Service 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
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.
| Test-ID | Specified value | |||
|---|---|---|---|---|
| min. | max. | |||
| 1 | Rich to lean sensor barrier voltage | - | 0.6241 V | |
| 2 | Lean to rich sensor barrier voltage | - | 0.6241 V | |
| 7 | Minimum voltage at sensor for test cycle | - | 0.450 V | |
| 8 | Maximum voltage at sensor for test cycle | 0.450 V | - | |
| 129 | Sensor voltage lean | 0 | 0.6241 V | |
| 130 | Sensor voltage rich | 0.6241 V | 1.2998 V | |
| 131 | Deceleration test | 0 V | 0.1599 V | |
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 appropriate Service 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 appropriate Service 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.
| Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket |
|---|---|
| 3 | 34 |
| 4 | 62 |
Specified value: 1.5 Ω 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 appropriate Service 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:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .