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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical issues.
• Allow the vehicle to cool down completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Steps:
  1. Locate the pre-catalytic and post-catalytic oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the old sensors from the exhaust system.
  4. Install the new oxygen sensors, ensuring they are torqued to the manufacturer's specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors to the new sensors.

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

• Tools Required: Socket set, exhaust pipe cutter (if needed), new gaskets.
• Steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Use the socket set to remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
  3. Carefully remove the catalytic converter and inspect it for damage or clogging.
  4. If replacement is necessary, install the new catalytic converter with new gaskets, ensuring all bolts are tightened to the manufacturer's torque specifications (typically around 40 lb-ft).
  5. Reconnect any exhaust components that were removed.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and let it idle for a few minutes.