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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle battery to avoid any electrical shorts.
• Ensure the vehicle is on a level surface and secure with wheel chocks.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:

   • The pre-catalytic sensor is typically located in the exhaust manifold. The post-catalytic sensor is found after the catalytic converter.

2. Remove the Oxygen Sensors:

   • Use an oxygen sensor socket to carefully unscrew the sensors from the exhaust system.
   • Disconnect the electrical connectors from each sensor.

3. Install New Oxygen Sensors:

   • Apply anti-seize compound to the threads of the new sensors (if required).
   • Screw in the new sensors by hand and then tighten them to the manufacturer's specifications (usually around 30 lb-ft).
   • Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components:

   • Loosen and remove any bolts or clamps securing the exhaust sections to the catalytic converter.
   • Carefully remove the old catalytic converter from its mounting points.

2. Install New Catalytic Converter:

   • Position the new catalytic converter in place and secure it with bolts or clamps.
   • Make sure all connections are tight and there are no exhaust leaks.

4. Clear Codes and Test Drive

1. Reconnect the Battery:

   • Reconnect the battery terminals securely.

2. Clear the Diagnostic Codes:

   • Use an OBD-II scanner to erase the P0420 code from the vehicle's memory.

3. Test Drive:

   • Drive the vehicle for a minimum of 20 minutes to allow the ECM to re-evaluate the performance of the new components.