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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle’s battery to ensure safety.
• Lift the vehicle using a jack and secure it with jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Apply penetrating oil to the O2 sensor threads if they are rusted.
  3. Using the O2 sensor socket, carefully remove the upstream oxygen sensor.
  4. Install the new upstream O2 sensor, ensuring it is tightened to the manufacturer's specifications (typically around 30 lb-ft).
  5. Repeat the process for the downstream oxygen sensor if applicable.

3. Check and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket (if needed).
• Sub-steps:
  1. Disconnect the exhaust pipe from the catalytic converter using a socket set.
  2. Remove any brackets holding the catalytic converter in place.
  3. Carefully lower the catalytic converter from the vehicle.
  4. Install the new catalytic converter, ensuring that it is oriented correctly.
  5. Reattach the exhaust pipe and any brackets, tightening all fasteners to manufacturer torque specifications.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle’s battery.
  2. Use an OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.