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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery negative terminal to ensure safety.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Unplug the electrical connectors from both sensors.
  3. Use an O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new sensors and torque them to the manufacturer’s specifications (typically around 30-40 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Ensure the vehicle is raised securely with jack stands.
  2. Remove any heat shields if present.
  3. Unbolt the catalytic converter from the exhaust system using a socket set.
  4. Inspect the old converter for clogging or damage.
  5. Install the new catalytic converter, ensuring proper alignment and torque to specifications (usually 15-25 ft-lbs for exhaust bolts).
  6. Reinstall any heat shields removed.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery negative terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and allow it to reach operating temperature.
  4. Perform a test drive to ensure that the check engine light does not reappear.