how to fix P0420 code on Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, exhaust pipe clamps.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work to avoid burns.

2. Replace Oxygen Sensors (if faulty)

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket wrench to remove the faulty O2 sensor(s).
3. Install new O2 sensor(s) and torque them to manufacturer specifications (typically 30-40 lb-ft).
4. Reconnect the electrical connectors for the O2 sensors.

3. Inspect/Replace Catalytic Converter

1. If the catalytic converter is damaged, remove it by loosening the exhaust clamps and bolts.
2. Ensure the exhaust system is supported to avoid stress on components.
3. Install the new catalytic converter, ensuring it is properly aligned with the exhaust system.
4. Torque the bolts to the recommended specifications (usually around 30 lb-ft).
5. Reconnect any exhaust clamps securely.

4. Clear Codes and Test Drive

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear any stored trouble codes.
3. Perform a test drive to ensure the vehicle operates normally and check if the check engine light reappears.