how to fix P0420 code on my 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

• Gather necessary tools and parts.
• Disconnect the vehicle's 12V battery to ensure safety.
• Allow the vehicle to cool if it has been running recently.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Locate the upstream and downstream oxygen sensors and disconnect the electrical connectors.
• Remove the sensors using the O2 sensor socket.
• Inspect the threads for damage.
• Install new oxygen sensors by threading them into their respective locations, and torque them to the manufacturer’s specifications (usually around 30 lb-ft).
• Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe gasket
• Inspect the catalytic converter for physical damage or signs of overheating.
• If the catalytic converter is faulty, remove the exhaust pipes connected to it using the socket set.
• Replace the old catalytic converter with a new unit, ensuring proper alignment and fit.
• Install new exhaust pipe gaskets and torque all bolts to manufacturer specifications.

4. Clear Codes and Test Drive

• Reconnect the vehicle's 12V battery.
• Use an OBD-II scanner to clear the P0420 code.
• Perform a test drive under various conditions to ensure the code does not reappear.