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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream sensor.
  3. Install the new upstream oxygen sensor, tightening it to the manufacturer's specifications (typically around 30 lb-ft).
  4. Repeat the process for the downstream sensor if it is also faulty.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary), gasket scraper.
• Sub-steps:
  1. Raise the vehicle and securely position it on jack stands.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Disconnect the exhaust pipes from the catalytic converter using a socket set or exhaust pipe cutter if corroded.
  4. Remove the catalytic converter and inspect it for internal damage or blockage.
  5. Install the new catalytic converter, ensuring proper alignment and secure connections.
  6. Reattach any heat shields or brackets.

4. Reset the Engine Control Unit (ECU)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use an OBD-II scanner to clear the P0420 code from the ECU.