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

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, and safety goggles.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Disconnect the negative terminal of the battery.
  2. Locate the upstream and downstream oxygen sensors near the catalytic converter.
  3. Use a socket wrench to remove the oxygen sensors.
  4. Install new oxygen sensors, ensuring they are torqued to manufacturer specifications (typically around 30 ft-lbs).
  5. Reconnect the battery terminal.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Lift the vehicle safely using jack stands.
  2. Remove any heat shields or components obstructing access to the catalytic converter.
  3. Unbolt the catalytic converter from the exhaust pipes using a socket set.
  4. Inspect the catalytic converter for physical damage or clogging.
  5. Install the new catalytic converter, ensuring proper alignment and torque specifications (commonly 25-35 ft-lbs).
  6. Reinstall any heat shields or components removed earlier.

4. Clear the Code and Test

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  2. Start the engine and allow it to reach normal operating temperature.
  3. Take the vehicle for a test drive to monitor performance and check for the return of the check engine light.