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

• Tools Required: OBD-II scanner, multimeter, infrared thermometer, socket set, jack stands, and safety goggles.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Find the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Remove oxygen sensors: Use a socket wrench to unscrew the sensors from the exhaust system.
3. Test sensors: Use the multimeter to check the resistance and voltage output. Replace any faulty sensors.
4. Install new sensors: Apply anti-seize compound on the threads of the new oxygen sensors and install them in the same position as the old ones.

3. Inspect and Replace Catalytic Converter

1. Remove catalytic converter: Use a socket set to unbolt the catalytic converter from the exhaust system.
2. Inspect converter: Check for physical damage or clogging. If damaged, proceed to replace it.
3. Install new catalytic converter: Position the new catalytic converter and secure it with bolts. Torque to manufacturer specifications.
4. Reconnect exhaust system: Ensure all joints are secure and sealed properly.

4. Clear Codes and Test

1. Reconnect the battery: Ensure the negative terminal is securely connected.
2. Clear error codes: Use the OBD-II scanner to erase the P0420 code from the vehicle's computer.
3. Test drive the vehicle: Drive for at least 20-30 minutes to allow the engine to reach operating temperature and monitor for any reoccurrence of the code.