why does my Volkswagen Passat B8 (2015-2022) have a check engine light with code P0455

Solution

1. Preparation

• Gather 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. Inspect and Replace the Gas Cap

• Tools Required: None
• Remove the gas cap and inspect the rubber seal for cracks or deterioration.
• If damaged, replace with a new OEM gas cap.

3. Examine and Repair EVAP Hoses

• Tools Required: Screwdriver set, pliers
• Inspect the EVAP hoses for cracks or disconnections.
• Replace any damaged hoses with OEM parts, ensuring secure connections.

4. Conduct a Smoke Test

• Tools Required: Smoke machine
• Connect the smoke machine to the EVAP system via the service port.
• Observe for smoke escaping from any leaks in the system and repair as necessary.

5. Test and Replace the Purge Valve (if necessary)

• Tools Required: Multimeter
• Disconnect the purge valve electrical connector and apply power to check if it opens.
• If the valve fails to operate, remove and replace it with a new OEM purge valve.

6. Reassemble and Recheck

• Reconnect all components, including the gas cap and battery terminal.
• Clear the DTCs using the OBD-II scanner and run the engine to verify the check engine light does not return.