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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative terminal of the battery.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor using the O2 sensor socket.
  • Sub-step: Disconnect the electrical connector.
  • Sub-step: Install the new oxygen sensor and torque to manufacturer's specifications (typically around 30 ft-lbs).
• Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter (if required)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)
• Disconnect the exhaust system from the catalytic converter.
  • Sub-step: Remove bolts using the socket set.
  • Sub-step: If applicable, cut the exhaust pipe with the exhaust pipe cutter.
• Remove the catalytic converter.
• Install the new catalytic converter and secure with bolts, torquing to manufacturer's specifications.
  • Sub-step: Ensure gaskets are replaced to prevent leaks.

4. Clear Codes and Test Drive

• Reconnect the negative terminal of the battery.
• Use an OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to monitor the performance and check for the return of the check engine light.