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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts during the repair.

2. Inspect and Replace Oxygen Sensors

1. Remove the battery terminal to ensure safety.
2. Locate the upstream and downstream oxygen sensors (usually found in the exhaust manifold and after the catalytic converter).
3. Disconnect the wiring harness from each oxygen sensor.
4. Use an O2 sensor socket to unscrew and remove the sensors.
5. Install the new oxygen sensors by reversing the removal process. Torque to manufacturer specifications (typically around 30 lb-ft).
6. Reconnect the battery terminal.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Raise the vehicle using a jack and secure it with jack stands.
2. Remove the exhaust system components (if necessary) to access the catalytic converter.
3. Inspect the catalytic converter for any signs of blockage or damage (e.g., dents, cracks, or melted internals).
4. If damaged, remove the catalytic converter by unbolting it from the exhaust pipes. Use penetrating oil if bolts are rusted.
5. Install the new catalytic converter, ensuring proper alignment and sealing.
6. Tighten all bolts to manufacturer specifications (typically around 30 lb-ft or per service manual).

4. Clear Codes and Test Drive

1. Reconnect the OBD-II scanner and clear the P0420 code.
2. Test drive the vehicle for at least 20 minutes under various driving conditions to ensure the code does not return.