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

Solution

1. Preparation

• Gather necessary tools and components.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to ensure safety while working on the electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use an O2 sensor socket to remove the faulty sensors.
  4. Install new oxygen sensors, ensuring they are torqued to the manufacturer's specifications.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed), gasket scraper.
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove any heat shields covering the catalytic converter.
  3. Disconnect the exhaust pipes at both the inlet and outlet of the catalytic converter using a socket set.
  4. If necessary, cut the exhaust pipes to remove the old catalytic converter.
  5. Install the new catalytic converter, ensuring proper alignment and securing with new gaskets and bolts.
  6. Reinstall heat shields and lower the vehicle.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use an OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and let it idle for a few minutes.