how to fix P0420 code on 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 all necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shock.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream and downstream sensors on the exhaust system.
2. Remove the Sensors: Use an oxygen sensor socket to unscrew and remove the sensors from their respective locations.
3. Inspect the Sensors: Check for any signs of damage or contamination.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors and install them, tightening to manufacturer specifications (typically around 30-40 Nm).
5. Reconnect the Electrical Connectors: Ensure that the connectors are secure.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components: Depending on access, you may need to remove parts of the exhaust system to reach the catalytic converter. Use a socket set and follow proper disassembly procedures.
2. Inspect the Catalytic Converter: Check for any physical damage, discoloration, or excessive soot buildup.
3. Remove the Old Converter: Detach the catalytic converter from the exhaust system, noting any gaskets or bolts used.
4. Install New Catalytic Converter: Place the new catalytic converter in position, ensuring it fits properly. Use new gaskets if needed and tighten the bolts to manufacturer specifications (typically 25-35 Nm).
5. Reassemble Exhaust Parts: Reattach any components removed during disassembly.

4. Reset the Check Engine Light

1. Reconnect the Battery: Ensure all connections are secure.
2. Clear Codes: Use the OBD-II scanner to clear the P0420 code and any other stored codes.