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 before beginning repairs.

2. Inspect and Clean Oxygen Sensors

• Tools Required: O2 sensor socket, brake cleaner, wire brush
  • Remove the downstream (post-catalytic converter) oxygen sensor.
  • Clean the sensor using brake cleaner and a wire brush.
  • Reinstall the sensor and ensure it is securely connected.

3. Replace Faulty Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, torque wrench
  • If cleaning does not resolve the issue, replace the upstream (pre-catalytic converter) and/or downstream oxygen sensor.
  • Install the new sensor(s) and torque to manufacturer specifications (usually around 30 lb-ft).

4. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket, possibly a saw (for cutting exhaust pipes)
  • If the catalytic converter is damaged or clogged, it needs replacement.
  • Remove any mounting bolts and brackets securing the catalytic converter.
  • Cut the exhaust pipe if necessary (use a saw) and remove the old catalytic converter.
  • Install the new catalytic converter using a new gasket, ensuring all bolts are tightened to specification.

5. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
  • After repairs, reconnect the battery and use an OBD-II scanner to clear the P0420 code.
  • Test drive the vehicle for a minimum of 20-30 minutes to allow the ECM to re-evaluate the catalytic converter performance.