my Toyota Highlander XU70 (2020-Present) shows a P0420 code, how do I fix it?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Using the O2 sensor socket, carefully unscrew and remove the faulty sensors.
  3. Install the new oxygen sensors and torque to manufacturer specifications (usually around 30 lb-ft).
  4. Reconnect the battery.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary).
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove any heat shields if obstructing access to the catalytic converter.
  3. Disconnect the exhaust pipes from the catalytic converter using a socket set or exhaust pipe cutter.
  4. Remove the catalytic converter from its mounting brackets.
  5. Install the new catalytic converter, ensuring gaskets are replaced and all connections are secure.
  6. Reinstall heat shields if removed.

4. Reset the Engine Control Module (ECM)

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