how to fix P0420 code in 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 necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the ignition off.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Sub-steps:
  1. Reconnect the battery and turn on the ignition without starting the vehicle.
  2. Use the OBD-II scanner to monitor the oxygen sensor readings.
  3. Check the voltage from the upstream sensor; it should fluctuate between 0.1V and 0.9V.
  4. Check the downstream sensor; it should remain relatively stable.

3. Replace Oxygen Sensors (if faulty)

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Remove the connectors for the faulty oxygen sensors.
  2. Using the socket set, carefully unscrew the old sensors from the exhaust system.
  3. Install new sensors by hand-tightening them first, then use the torque wrench to tighten them to the manufacturer’s specified torque.
  4. Reconnect the electrical connectors.

4. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Jack and jack stands, socket set, exhaust gasket sealant.
• Sub-steps:
  1. Safely raise the vehicle using jack stands.
  2. Disconnect the catalytic converter from the exhaust system by removing the mounting bolts.
  3. Inspect the mating surfaces and clean them if necessary.
  4. Install the new catalytic converter, ensuring proper alignment and using new gaskets if required.
  5. Tighten the bolts to the manufacturer’s specified torque.

5. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the system.
  2. Take the vehicle for a test drive to monitor performance and ensure the check engine light does not reappear.