how to check for P0420 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety gloves, safety glasses
• Ensure the vehicle is parked on a level surface and the engine is cool. Disconnect the battery negative terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors connected to the exhaust system.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust pipes.
  4. Install the new oxygen sensors by threading them into the exhaust and tightening them to the manufacturer’s specified torque (typically around 30-40 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Check and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Inspect the catalytic converter for any visible damage and confirm that it is not clogged.
  2. If damage is found, remove the catalytic converter by loosening the bolts securing it to the exhaust system.
  3. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  4. Tighten all bolts to the manufacturer’s specified torque (typically around 30-40 lb-ft).

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery negative terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the computer.
  3. Start the engine and let it reach operating temperature.
  4. Take the vehicle for a test drive under various driving conditions to ensure proper operation and check for reoccurrence of the code.