how to fix P0420 code in 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 high-voltage battery (follow Tesla’s safety guidelines).
• Ensure the car is on a level surface and securely lifted if necessary.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors from the exhaust system using the O2 sensor socket.
• Inspect sensors for contamination or damage; replace if necessary.
• Install new sensors, tightening to the manufacturer's specified torque settings (usually around 30 Nm).

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, exhaust hangers tool, torque wrench.
• Inspect the catalytic converter for signs of damage or blockage.
• If replacement is necessary, loosen the bolts securing the catalytic converter to the exhaust system and remove it.
• Install the new catalytic converter, ensuring proper alignment and secure it with bolts to the specified torque (typically 40-50 Nm).
• Reconnect any exhaust hangers as needed.

4. Reconnect Battery and Clear Codes

• Reconnect the high-voltage battery.
• Use the OBD-II scanner to clear the P0420 error code from the engine's computer.
• Perform a short drive cycle to allow the vehicle to relearn sensor values.