Oxygen Sensor 2 and Sensor Regulation After Catalytic Converter, Checking

Oxygen Sensor 2 and Sensor Regulation after Catalytic Converter, Checking

The following procedure is used to diagnose Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) which is controlled by the Engine Control Module (ECM) 2 (J624 ).

• When servicing the electrical harness connector terminals of the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) , use only gold-plated terminals.

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Engine Control Module (ECM) 2 (J624) fuses OK.

• Oxygen Sensor (O2S) 2 (behind Three Way Catalytic Converter (TWC)) Heater (Z30) 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.

Function test

- Perform the function test located in diagnostic mode 06. Refer to => [ Test-ID 06 ($06): Oxygen Sensor
Monitor Bank 2 - Sensor 2 ] Diagnostic Mode 06 - Read Test Results for Specific Diagnostic Functions.

If specified values are obtained:

- End diagnosis and switch the ignition off.

If the specified values are not obtained:

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ General Diagnosis ] General Diagnosis.

Start diagnosis

- Raise the vehicle.

- Disconnect the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) - 3 -.





Checking primary voltage

- Switch the ignition on.

- Using a multimeter, check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) 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) 2 Behind Three Way Catalytic Converter (TWC) (G131). Refer to Fuel Injection and Ignition 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 Fuel Injection and Ignition Repair Information.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Engine Control Module (ECM) 2 (J624 ). Refer to => [ Engine Control Module 1, Removing and Installing ] Engine Control Module 1, Removing and Installing.

- Using a Multimeter, check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) electrical harness connector terminals to the Engine Control Module (ECM) 2 (J624) electrical harness connector T94 terminals for an open circuit.









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 Engine Control Module (ECM) 2 (J624 ). Refer to => [ Engine Control Module 1, Removing and Installing ] Engine Control Module 1, Removing and Installing.

Final procedures

After 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.