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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and engaged in park (or neutral for manual transmission).
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench, multimeter.
• 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 upstream sensor first, followed by the downstream sensor.
  4. Install the new oxygen sensors, tightening them to the manufacturer's torque specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

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

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed), gasket scraper, new gaskets.
• Steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Inspect the catalytic converter for any signs of damage.
  3. If replacement is needed, disconnect the exhaust pipe at both ends of the catalytic converter.
  4. Remove the old catalytic converter using the socket set and exhaust pipe cutter if necessary.
  5. Clean the mounting surfaces with a gasket scraper to ensure a good seal.
  6. Install the new catalytic converter and torque the bolts to the manufacturer's specifications.
  7. Reconnect the exhaust pipe and secure all connections.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.