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

Learn how to diagnose and fix P0420 catalyst system efficiency 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 flat surface and the engine is cool.
• Disconnect the battery to avoid electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors:
   • The upstream sensor is before the catalytic converter, and the downstream sensor is after it.
2. Remove the oxygen sensors:
   • Use an oxygen sensor socket or wrench to unscrew and remove both sensors.
3. Install new oxygen sensors:
   • Ensure the threads are clean, and apply anti-seize compound if recommended.
   • Torque to the manufacturer’s specifications (usually around 30-40 lb-ft).
4. Reconnect the battery.

3. Inspect and Replace Catalytic Converter

1. Prepare for removal:
   • Raise the vehicle using a jack, and secure it with jack stands.
   • Ensure adequate lighting for visibility.
2. Remove the catalytic converter:
   • Loosen and remove the bolts securing the catalytic converter to the exhaust system.
   • Carefully detach the catalytic converter from its mounting.
3. Install the new catalytic converter:
   • Position the new component in place and secure it with bolts.
   • Torque to manufacturer specifications (usually around 30-45 lb-ft).
4. Reconnect any exhaust sensors as necessary.

4. Reset the OBD-II codes

• Use an OBD-II scanner to erase the P0420 code from the system.
• Perform a drive cycle to allow the vehicle's systems to monitor and verify repairs.