Passat EVAP Stalling Issue Fixed: Mechanic Guide

Having experienced nearly identical symptoms with my 2014 Passat GTE Hybrid, the check engine light came on due to a failing EVAP system. The fuel tank pressure sensor was detecting irregular pressure, causing stalling at idle. The main issue was traced to three components: A clogged purge valve filled with carbon deposits, Damaged vapor lines leading to the charcoal canister, A loose gas cap that wasnt sealing properly The stalling happened because the engine management system was getting incorrect readings from the fuel tank ventilation system. These symptoms typically start mild but can develop into more serious problems if left unaddressed. The repair involved: 1. Cleaning the EVAP system components 2. Replacing the purge valve 3. Testing the entire fuel tank pressure system 4. Replacing damaged vapor lines 5. Installing a new gas cap seal While not immediately dangerous, these issues require prompt attention since they affect both emissions control and fuel system operation. The check engine light will typically stay on until all components are properly fixed and the system is reset. Worth noting that hybrid models can be more sensitive to EVAP system issues due to their sealed fuel tank design and pressure management requirements.

Thanks for sharing your experience. Had a similar issue with my VW and curious about the final cost breakdown. The check engine light kept coming on and the tank ventilation problems got worse over time. My fuel tank pressure was also acting up, just like yours. Did the repair hold up well afterwards? Also, how much did you end up paying for all those fixes? Might need to get mine sorted soon and trying to budget for it.

After getting the repairs done, the tank ventilation system has worked flawlessly for over 8 months now. The main problem turned out to be clogged hoses affecting the EVAP system, which caused those erratic pressure sensor readings in the fuel tank. The total repair came to 175€, which included cleaning the entire system and replacing the problematic hoses. Much more reasonable than I initially feared, especially considering how the check engine light problems completely disappeared afterwards. The repair shop did a thorough pressure test of the entire fuel tank system to ensure everything was sealed properly. No more stalling issues since then, and the engine runs smoothly at idle now. Definitely worth getting it fixed properly rather than letting it deteriorate further.

I finally took my Passat to a new mechanic last week after seeing these responses. The check engine light issue turned out to be exactly what others described, problems with the EVAP system and tank ventilation. The mechanic found a cracked vapor line and a failing purge valve that were causing the pressure issues in the fuel tank. Total cost came to 195€ for parts and labor, which included: New purge valve, Replacement vapor lines, System cleaning, Full pressure test, New gas cap (mine was worn out) The repair took about 3 hours and the car runs perfectly now. No more stalling at idle and the check engine light has stayed off. Really glad I got it fixed before it led to bigger problems. Huge relief to have this sorted with a trustworthy mechanic who actually took the time to explain the issues.