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

Solution

1. Preparation

• Gather all necessary tools and parts before starting the repair.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.

2. Disconnect the Battery

• Use a wrench to disconnect the negative terminal of the battery to prevent electrical short circuits.

3. Inspect and Replace O2 Sensors (if necessary)

• Tools Required: O2 sensor socket, torque wrench
  • a. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) O2 sensors.
  • b. Disconnect the electrical connectors from both sensors.
  • c. Use the O2 sensor socket to remove the sensors from their respective locations.
  • d. Install the new O2 sensors, ensuring they are torqued to manufacturer specifications (usually around 30 lb-ft).
  • e. Reconnect the electrical connectors.

4. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, wrench, exhaust hanger removal tool
  • a. Raise the vehicle safely using jack stands or a lift.
  • b. Remove any heat shields covering the catalytic converter.
  • c. Disconnect the exhaust pipe from the catalytic converter using the socket set.
  • d. Remove any hangers or brackets securing the catalytic converter and slide it out.
  • e. Install the new catalytic converter, ensuring all connections are secure and torqued to specifications.
  • f. Reinstall any heat shields removed during the process.

5. Reconnect the Battery

• Reconnect the negative battery terminal and ensure it is tight.

6. Clear Codes and Test Drive

• Use an OBD-II scanner to clear the P0420 code.
• Take the vehicle for a test drive to ensure that the check engine light does not reappear.