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

Solution

1. Preparation

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

2. Inspect and Repair Exhaust System

• Tools Required: Socket set, jack and jack stands
• Inspect the entire exhaust system for leaks or loose connections.
  • Tighten any loose bolts or clamps.
  • Replace damaged gaskets or pipes as needed.

3. Test and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Check the functionality of the upstream and downstream oxygen sensors.
  • If either sensor is faulty, replace it.
  • Disconnect the electrical connector and remove the sensor using the O2 sensor socket.
  • Install the new sensor and torque to manufacturer's specifications (typically around 30 ft-lbs).

4. Inspect and Replace Catalytic Converter if Necessary

• Tools Required: O2 sensor socket, socket set, exhaust pipe cutter
• If the catalytic converter is damaged or inefficient:
  • Remove the exhaust pipes connected to the catalytic converter.
  • Cut the exhaust pipe if necessary and remove the old catalytic converter.
  • Install the new catalytic converter and reattach all exhaust components, ensuring secure connections.
  • Torque all bolts to specifications.

5. Reset the ECU

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the ECU.