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

Learn how to diagnose and fix P0420 catalyst efficiency 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 level surface and the parking brake is engaged.
• Disconnect the battery (negative terminal).

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors along the exhaust system.
  • Use a socket wrench to carefully remove the sensors.
  • Inspect the threads and connectors for damage or corrosion.
  • Replace any faulty oxygen sensors with new, compatible parts.
  • Torque the new sensors to the manufacturer’s specified value (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  • Locate the catalytic converter in the exhaust system.
  • Use a wrench to detach the exhaust pipes leading to and from the catalytic converter.
  • Inspect the catalytic converter for signs of damage, such as dents or excessive discoloration.
  • If replacement is needed, install the new catalytic converter and secure it with the exhaust clamps, ensuring a proper seal.
  • Torque bolts to manufacturer specifications, typically around 30 ft-lbs.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  • Reconnect the negative terminal of the battery.
  • Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.
  • Conduct a test drive to allow the vehicle’s systems to recalibrate.