how to fix P0420 code on Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0420 exhaust system issue in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.
• Disconnect the vehicle's 12V battery to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Using the O2 sensor socket, carefully unscrew the upstream sensor and inspect its condition. Repeat for the downstream sensor.
  3. Test each sensor using a multimeter to ensure they are within specification. Replace any faulty sensors with new ones.
  4. Reinstall the new sensors, ensuring they are tightened to the manufacturer’s specifications (typically around 30 lb-ft).

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

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Sub-steps:
  1. If the catalytic converter is determined to be faulty, disconnect the exhaust pipes at the flanges using the socket set.
  2. Carefully remove the catalytic converter from the exhaust system.
  3. Install the new catalytic converter, ensuring proper alignment and fitment.
  4. Torque the bolts to the manufacturer's specifications (typically around 30 lb-ft).
  5. Reconnect the exhaust pipes securely.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle’s 12V battery.
• Use the OBD-II scanner to clear the P0420 code and any other related codes.