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

Solution

1. Preparation

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

2. Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Apply penetrating oil to the sensor threads and let it sit for a few minutes.
  3. Disconnect the electrical connector from the O2 sensor.
  4. Remove the faulty O2 sensor using the O2 sensor socket.
  5. Install the new O2 sensor by threading it into the exhaust and tightening it to the manufacturer's specifications (usually about 30-40 lb-ft).
  6. Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter, gasket scraper.
• Sub-steps:
  1. Raise the vehicle securely on jack stands.
  2. Remove the exhaust hangers to free the catalytic converter.
  3. Use an exhaust pipe cutter to detach the catalytic converter from the exhaust piping.
  4. Clean the mating surfaces of the exhaust manifold and the exhaust pipe.
  5. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  6. Use a torque wrench to tighten the bolts to the manufacturer's specifications (typically around 25-30 lb-ft).
  7. Reinstall the exhaust hangers.

4. Clear Codes and Test

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Drive the vehicle for a short distance to ensure the code does not reappear.