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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
  4. Inspect the threads and connectors for any damage. Replace if necessary.
  5. Install the new sensors, ensuring they are tightened to the manufacturer's specifications (usually around 30 ft-lbs).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed)
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove the exhaust heat shield if applicable.
  3. Disconnect the exhaust pipes at both ends of the catalytic converter using a socket set or exhaust pipe cutter.
  4. Remove any mounting brackets or bolts securing the catalytic converter.
  5. Install the new catalytic converter, ensuring a proper fit and secure connections.
  6. Reattach the exhaust system and heat shield as necessary.

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 vehicle's computer.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to monitor for any recurrence of the P0420 code.