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 shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and extension.
• Steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Using the O2 sensor socket, unscrew the sensors from their respective locations.
  3. Install new oxygen sensors, ensuring they are properly tightened to manufacturer specifications (typically around 30 Nm).
  4. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, and exhaust sealant.
• Steps:
  1. Remove any heat shields or brackets securing the catalytic converter.
  2. Disconnect the exhaust pipes from the catalytic converter.
  3. Remove the catalytic converter by unscrewing the mounting bolts.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Torque the bolts to the manufacturer’s specifications (check service manual for exact values).
  6. Apply exhaust sealant to joints where pipes connect to ensure a leak-free installation.

4. Clear Error Codes and Test Drive

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