how to fix P0401 EGR flow insufficient code on Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0401 EGR flow insufficient 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 level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Remove the EGR Valve

• Locate the EGR valve on the engine.
• Remove any electrical connectors and vacuum hoses attached to the EGR valve.
• Use a socket set to remove bolts securing the EGR valve to the intake manifold.
• Carefully remove the EGR valve, taking care not to damage the gasket.

3. Inspect and Clean

• Inspect the EGR valve for carbon buildup or damage. If dirty, clean it using an EGR valve cleaner and a soft brush.
• Check the EGR passages in the intake manifold for blockages and clean as needed.
• Inspect the gasket for wear; replace it if it is damaged or degraded.

4. Reinstall the EGR Valve

• Place a new gasket onto the intake manifold.
• Reinstall the EGR valve, securing it with bolts to the specified torque (refer to the service manual for exact torque specifications).
• Reattach electrical connectors and vacuum hoses.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.
• Monitor the engine for any abnormal sounds or check engine light re-illumination.