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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.
• Disconnect the vehicle's battery to prevent electrical shorts.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the electrical connectors from the sensors.
  3. Use a socket wrench to remove the sensors from their threaded ports.
  4. Install the new oxygen sensors, tightening them to the manufacturer's specified torque (usually around 30-40 ft-lbs).
  5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Remove the exhaust heat shield if it obstructs access to the catalytic converter.
  2. Disconnect the exhaust pipes at both ends of the catalytic converter using a socket set.
  3. Remove mounting bolts and brackets securing the catalytic converter.
  4. Carefully remove the catalytic converter from its position.
  5. Install the new catalytic converter, ensuring proper alignment and sealing.
  6. Reattach the exhaust pipes and secure them with bolts, torquing them to specifications.

4. Reset the ECU

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use an OBD-II scanner to clear the P0420 code from the vehicle's ECU.
  3. Take the vehicle for a short drive to monitor for any reoccurrence of the code.