VW Atlas Idle Stall Linked to Fuel Tank Vent System

Had similar symptoms on a 2019 VW Tiguan 2.0T. The stalling at idle paired with check engine light pointed to a defective activated charcoal filter in the emission control system. The charcoal filter failure affects fuel tank pressure regulation, causing irregular idle. The pressure sensor readings were unstable, indicating the system could not maintain proper fuel tank ventilation. This specific failure also triggered the check engine light due to the emission control system detecting incorrect pressure values. The repair required replacing the complete charcoal canister assembly and running a system diagnostic to ensure proper fuel tank ventilation. Not a complex fix, but important to address promptly as it affects both emissions and engine performance. Symptoms matched exactly what you describe, perfect operation while driving but stalling at stops. The root cause was the system failure in maintaining correct fuel tank pressure. Would recommend finding a shop specializing in VW fuel system diagnostics, as proper testing equipment is essential for confirming this specific issue. This is not a major mechanical problem, but it needs proper diagnosis and repair to prevent potential long-term fuel system damage. The repair resolved all symptoms with no recurrence.

Thanks for sharing your experience with the charcoal filter issue. I had an identical problem with my Atlas, same stalling and check engine symptoms from a faulty purge valve in the emission control system. The leak detection diagnostics confirmed it was causing irregular pressure readings. Did the repair cost stay under 500€? Also curious if youve experienced any other fuel efficiency issues since getting it fixed? My fuel consumption seems slightly higher than before, but could just be my driving style.

After getting the defective activated charcoal filter replaced, my fuel efficiency actually returned to normal. The total repair came to 275€, which included the new filter and diagnostic work. The EVAP system is now maintaining proper pressure, and I havent seen any check engine lights since the fix. The air flow and pressure readings are now stable according to the system diagnostic report. The mechanic confirmed the new charcoal filter restored proper fuel tank ventilation, eliminating the previous system failure that was causing the stalling issues. Make sure your shop checks the complete emission control system when doing the repair. A proper diagnosis should include testing the purge valve and pressure sensor readings to confirm everything is working correctly after the fix. My car has been running perfectly for several months now with no stalling or efficiency issues. The slightly higher fuel consumption you are noticing might be temporary while the system readjusts, but should normalize soon.

Great news, I finally got this sorted out after following your advice about the charcoal filter. Took my Atlas to a different shop that specializes in VW fuel systems. Their leak detection tests confirmed the faulty purge valve was the culprit, just as you described. The repair cost came to 320€ total. They replaced the purge valve and ran a full emission control system diagnostic. My air flow readings are now stable and the check engine light hasnt come back. Most importantly, no more stalling at red lights. After 2 weeks of driving, my fuel efficiency has actually improved compared to before. The mechanic explained the bad valve was making the engine run rich, so fixing it helped optimize the fuel mixture. Definitely worth getting a second opinion and having it properly diagnosed. Thanks again for pointing me in the right direction with this. The new shop did a much more thorough job finding and fixing the real problem.