how to fix the P0420 code on my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface, and engage the parking brake.
• Disconnect the battery to ensure safety while working on the electrical components.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, wrench set
• Procedure:
  1. Locate the upstream and downstream O2 sensors on the exhaust system.
  2. Use the O2 sensor socket to disconnect and remove the sensors.
  3. Install the new O2 sensors by threading them into place and tightening them to manufacturer specifications (typically around 30 Nm).
  4. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, gasket scraper
• Procedure:
  1. If the catalytic converter is found to be damaged or clogged, remove the exhaust pipe connected to it using a socket set.
  2. Use a gasket scraper to clean any old gasket material from the mating surfaces.
  3. Install the new catalytic converter, ensuring it is oriented correctly.
  4. Torque the bolts to the manufacturer's specifications (usually around 40-50 Nm).
  5. Reconnect any exhaust pipes and ensure all connections are tight.

4. Clear Codes and Test Drive

• Procedure:
  1. Use an OBD-II scanner to clear the P0420 code from the vehicle's memory.
  2. Start the engine and let it idle for a few minutes.
  3. Take the vehicle for a test drive under various conditions (city and highway) to ensure the check engine light does not return.