how to fix P0420 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Gather necessary tools and replacement parts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Using a socket wrench, carefully remove the oxygen sensors.
  3. Install the new oxygen sensors and torque them to the manufacturer's specifications (typically around 30 lb-ft).
  4. Reconnect the electrical connectors for both sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust heat shield if applicable.
  2. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using a socket set.
  3. Inspect the catalytic converter for physical damage or excessive carbon buildup.
  4. Install the new catalytic converter, ensuring proper alignment, and torque bolts to manufacturer specifications (typically around 40 lb-ft).
  5. Reinstall the exhaust heat shield if removed.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use an OBD-II scanner to clear the P0420 code from the vehicle's memory.
  3. Start the engine and allow it to reach operating temperature.