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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Remove the upstream (pre-catalytic) oxygen sensor using an oxygen sensor socket.
• Inspect the sensor for carbon buildup or damage.
• If faulty, replace the oxygen sensor with a quality OEM part.
• Reinstall the sensor and reconnect the wiring harness.

3. Inspect the Catalytic Converter

• Check for any signs of physical damage or rattling from the catalytic converter.
• Use a pressure gauge to measure back pressure; excessive pressure indicates a blockage.
• If the catalytic converter is defective, remove it:
  • Support the vehicle on jack stands.
  • Unbolt the exhaust pipes from the catalytic converter.
  • Remove any heat shields if necessary.
  • Install the new catalytic converter and secure it with new gaskets and bolts.
• Ensure all exhaust connections are tight to prevent leaks.

4. Clear the Codes

• Reconnect the battery.
• Use an OBD-II scanner to erase the P0420 code and any other related codes.

5. Test Drive

• Start the engine and allow it to reach normal operating temperature.
• Take the vehicle for a test drive to ensure the check engine light does not reappear and performance issues are resolved.