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

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

Solution

1. Preparation

• Gather Tools: OBD-II scanner, multimeter, socket set, safety glasses, and gloves.
• Safety Precautions: Ensure the vehicle is turned off and cooled down before starting the inspection.

2. Inspect and Replace O2 Sensors (if necessary)

1. Locate O2 Sensors: Identify the upstream and downstream O2 sensors located before and after the catalytic converter.
2. Disconnect Wiring Harness: Carefully disconnect the wiring harness from the O2 sensor.
3. Remove O2 Sensor: Use a socket to unscrew and remove the O2 sensor from the exhaust system.
4. Install New O2 Sensor: Apply anti-seize compound to the threads of the new O2 sensor, then install and torque to manufacturer specifications (usually around 30 ft-lbs).
5. Reconnect Wiring: Reattach the wiring harness to the new O2 sensor.

3. Examine and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components: If necessary, remove any exhaust components obstructing access to the catalytic converter.
2. Unbolt Catalytic Converter: Use a socket set to unbolt the catalytic converter from the exhaust system.
3. Install New Catalytic Converter: Position the new catalytic converter in place, then bolt it securely, ensuring to follow torque specifications.
4. Reattach Exhaust Components: Reinstall any components removed during the process, ensuring all connections are tight and leak-free.

4. Clear Error Codes

• Use the OBD-II scanner to clear the P0420 code and any other related codes from the vehicle's computer.