how to fix P0420 code on my Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.
• Gather all necessary tools and parts before starting.
• Disconnect the negative battery terminal for safety.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the pre and post-catalytic converter oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust system.
  4. Install the new oxygen sensors and torque them to the manufacturer's specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields covering the catalytic converter.
  2. Disconnect the exhaust pipes connected to the catalytic converter using a socket set.
  3. Remove the catalytic converter from its mounting brackets.
  4. Install the new catalytic converter and secure it with the appropriate hardware, torquing to specification.
  5. Reattach any heat shields removed in the process.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to verify that the check engine light does not reappear.