how to diagnose P0420 code on Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the vehicle to cool down before working on the exhaust system.

2. Replace Faulty Oxygen Sensors

1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Use an O2 sensor socket to remove the faulty oxygen sensors.
3. Install the new sensors, ensuring they are torqued to the manufacturer’s specifications (usually around 30 ft-lbs).
4. Reconnect the electrical connectors securely.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Remove the exhaust heat shield to access the catalytic converter.
2. Loosen and remove the bolts securing the catalytic converter to the exhaust manifold and exhaust pipe using a socket set.
3. Carefully remove the catalytic converter from the vehicle.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
5. Torque the bolts to the manufacturer's specifications (typically around 40-50 ft-lbs).
6. Reinstall the exhaust heat shield.

4. Clear Codes and Test

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code from the ECM.
3. Start the engine and allow it to reach operating temperature.
4. Take the vehicle for a test drive to ensure that the check engine light does not reappear.