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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Use a socket wrench to carefully remove the oxygen sensors.
3. Inspect the sensors for any physical damage or contamination.
4. Install new oxygen sensors:
   • Apply anti-seize compound to the threads (if applicable).
   • Torque to manufacturer specifications (typically around 30 ft-lbs).
5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

1. Remove the exhaust heat shield (if applicable) using a socket set.
2. Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
3. Inspect the catalytic converter for damage or clogging.
4. If faulty, install a new catalytic converter:
   • Ensure all gaskets are replaced.
   • Torque bolts to manufacturer specifications (refer to service manual).
5. Reinstall the exhaust heat shield.

4. Clear Codes and Test Drive

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code.
3. Test drive the vehicle for at least 20 minutes to ensure the issue does not reoccur.