how to fix P0420 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, mechanic's gloves, safety glasses, jack and jack stands, socket set, torque wrench.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the pre-catalytic and post-catalytic oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket to remove the sensors from their respective locations.
  4. Install new oxygen sensors, tightening to the manufacturer’s torque specification (usually around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove the exhaust pipe connections to the catalytic converter using a socket set.
  3. Remove any mounting brackets holding the catalytic converter in place.
  4. Install the new catalytic converter, ensuring all gaskets and seals are in place.
  5. Torque all bolts to the manufacturer’s specifications (check service manual for specific values).
  6. Reconnect the exhaust pipe and any brackets removed.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and let it warm up.
  4. Take the vehicle on a test drive to ensure the check engine light does not return.