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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove O2 Sensors:

   • Locate the upstream and downstream oxygen sensors.
   • Use an O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
   • Tools Required: O2 sensor socket, ratchet, and extension.

2. Install New O2 Sensors:

   • Apply anti-seize compound on the threads of the new sensors.
   • Install the new sensors and torque to manufacturer specifications (typically around 30 lb-ft).
   • Reconnect electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components:

   • Loosen and remove the bolts securing the catalytic converter to the exhaust pipe and manifold.
   • Support the exhaust system as needed to prevent damage.
   • Tools Required: Socket set, exhaust hanger removal tool.

2. Install New Catalytic Converter:

   • Position the new catalytic converter and secure it to the exhaust system.
   • Torque bolts to manufacturer specifications (typically around 25 lb-ft).
   • Reconnect any sensors or components removed during the process.

4. Clear Codes and Test Drive

1. Reconnect Battery:

   • Reconnect the battery and ensure all connections are secure.

2. Clear OBD-II Codes:

   • Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.

3. Test Drive:

   • Take the vehicle for a test drive to ensure the check engine light does not reappear and the vehicle operates smoothly.