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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical issues.
• Allow the vehicle to cool down before starting work on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate and remove the upstream O2 sensor (before the catalytic converter) using the O2 sensor socket.
  2. Inspect the sensor for damage; replace if necessary.
  3. Repeat for the downstream O2 sensor (after the catalytic converter).
  4. Install new O2 sensors and torque to manufacturer specifications (typically 30-40 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hangers remover tool.
• Sub-steps:
  1. Remove any heat shields covering the catalytic converter.
  2. Use the socket set to unbolt the catalytic converter from the exhaust pipes.
  3. Inspect the catalytic converter for physical damage or clogging.
  4. If damaged, install a new catalytic converter using new gaskets and bolts, torquing them to manufacturer specifications (usually 30-50 ft-lbs).
  5. Reinstall the heat shields if applicable.

4. Clear Codes and Test

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear any trouble codes from the vehicle's memory.
  3. Start the engine and let it reach operating temperature.
  4. Perform a test drive to ensure the check engine light does not reappear.