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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, wrench set.
• Remove the upstream oxygen sensor:
  1. Locate the upstream oxygen sensor on the exhaust manifold.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Disconnect the electrical connector.
• Install the new oxygen sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Thread the new sensor into the manifold and tighten it to the manufacturer’s torque specifications (typically around 30 ft-lbs).
  3. Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Remove the old catalytic converter:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Use the socket set to unbolt the catalytic converter from the exhaust system.
  3. If necessary, use the exhaust pipe cutter to remove any compromised sections.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Bolt it securely to the exhaust system, ensuring proper alignment.
  3. Tighten bolts to the manufacturer’s specifications (typically between 25-35 ft-lbs).

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Clear the P0420 code using the OBD-II scanner.
• Test drive the vehicle for at least 20 miles to ensure the check engine light does not reappear.