Oxygen Sensors After Catalytic Converter, Checking
Oxygen Sensors After Catalytic Converter, Checking
This procedure is used to diagnose Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 or Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131.
NOTE: When servicing the electrical harness connector of the Oxygen Sensors (O2S) Behind Three Way Catalytic Converter (TWC) , 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.
- The Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 fuse 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 degrees C.
Function test
Perform a function test of the Heated Oxygen Sensors (HO2S).
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. General Diagnosis
Start diagnosis
- Disconnect the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector - 2 -.
To disconnect the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 , perform the following steps:
- Remove the screw - arrow - retaining the coolant reservoir.
- Disconnect the Engine Coolant Level (ECL) Warning Switch F66 electrical connector from the bottom of the coolant reservoir and set aside the coolant reservoir with the coolant hoses - 1 - and - 2 - connected.
- Disconnect the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 electrical harness connector - 2 -.
Checking primary voltage
- Using a Multimeter , check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) electrical harness connector terminals 3 to 4 for voltage.
- Switch the ignition on.
Specified value: 0.400 to 0.500 V.
- Switch the ignition off.
If the specified value was obtained:
- Replace the faulty Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC).
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 Engine Control Module (ECM) J623.
- Using a Multimeter , check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) electrical harness connector terminals to the Engine Control Module (ECM) J623 electrical harness connector T94 terminals for an open circuit.
Oxygen Sensor (O2S) Behind Engine Control Module (ECM) J623
Three Way Catalytic Converter electrical harness connector T94
(TWC) G130 electrical harness terminals or test box sockets
connector terminals
3 76
4 77
Oxygen Sensor (O2S) 2 Behind Engine Control Module (ECM)
Three Way Catalytic Converter J623 electrical harness connector
(TWC) G131 electrical harness T94 terminals or test box sockets
connector terminals
3 54
4 55
Specified value: 1.5 Ohms Max.
If any of the specified values are 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 detected in the wiring:
- Replace the Engine Control Module (ECM) J623.
Final procedure
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- End of diagnosis.