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

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, torque wrench, vacuum gauge, and replacement parts if necessary.
• Disconnect the battery to prevent electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors (if necessary)

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket to remove the oxygen sensor(s) from their respective locations.
3. Inspect the sensor threads and connector for damage.
4. Install the new oxygen sensor(s) by screwing it into place, ensuring proper torque (typically around 30 lb-ft).
5. Reconnect the electrical connector(s) and ensure they are secure.

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

1. Check for any signs of damage or clogging in the catalytic converter.
2. If replacement is needed, remove the exhaust pipes connected to the catalytic converter using a socket set.
3. Carefully detach the catalytic converter from the exhaust system, noting the orientation and position.
4. Install the new catalytic converter, making sure to align it correctly.
5. Reattach the exhaust pipes and tighten all connections to the manufacturer's specifications.

4. Clear Codes and Test Drive

1. Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
2. Conduct a test drive for at least 20 minutes to allow the vehicle to enter closed-loop operation.
3. Re-scan the vehicle to ensure that no codes have returned.