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

Learn how to diagnose and fix P0420 check engine light on Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the battery to prevent any electrical shorts while working.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Remove the upstream oxygen sensor using an oxygen sensor socket.
  3. Inspect the sensor for any signs of damage or contamination.
  4. Replace with a compatible new oxygen sensor if necessary (ensure it matches OEM specifications).
  5. Repeat steps 2-4 for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Inspect the catalytic converter for any physical damage or signs of clogging.
  2. If replacement is required, unbolt the catalytic converter from the exhaust system.
  3. Install a new catalytic converter, ensuring the proper alignment and sealing.
  4. Torque the bolts to the manufacturer's specifications (check service manual for exact values).

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals, ensuring they are secured tightly.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the vehicle and allow it to reach normal operating temperature.