VW Fox Stalling: Fuel Tank Ventilation System Fix

I had a very similar issue with my 2013 VW Polo. After experiencing the same symptoms, check engine light, stalling at idle, and rough running, it turned out to be a defective activated charcoal filter affecting the entire fuel tank ventilation system. The purge valve and pressure sensor readings were showing incorrect values, causing the engine management system to get confused about the air flow. This led to poor fuel efficiency and the stalling issues you described. The workshop diagnosed it by checking the emission control system and found that the charcoal filter was completely clogged. The repair included: Replacing the activated charcoal filter, Testing the purge valve operation, Resetting the engine management system, Verifying proper fuel tank pressure Total cost was 275€ including parts and labor. Since the fix, the car has been running smoothly with no more stalling or check engine lights. Before giving more specific advice, could you share: Current mileage on your Fox, Whether you notice any fuel smell, If the problem occurs more after refueling, Whether the check engine light is constant or intermittent This information would help determine if your issue is identical to what I experienced with my Polo.

Had my VW Fox serviced last month at 44107km. The shop did a thorough EVAP system test and found the pressure sensor was giving faulty readings when communicating with the engine control module. Like your case, it led to system failure messages and stalling issues. After replacing both the pressure sensor and purge valve, the problems cleared up completely. The poor air flow readings were causing the engine management to run a much richer fuel mixture than needed. No more check engine lights or stalling since the repair. The fix cost 320€ total and took about 2 hours of labor. Make sure they test the entire EVAP system and not just individual components.

Thanks for sharing those details about your Fox repair. The symptoms and solution match exactly what I dealt with on my Polo. These EVAP system issues are pretty common across VW models from that era. When my purge valve failed, I also noticed the system failure would trigger more frequently right after filling up the fuel tank. The faulty pressure readings really confused the engine management, leading to that rich fuel mixture you mentioned. One thing I learned from my repair, the air flow sensor readings can be affected if the charcoal filter starts breaking down, which then contaminates the purge valve. Had I caught the check engine warnings earlier, I might have avoided needing both parts replaced. Good call on having them check the complete EVAP system. My first repair attempt only replaced the purge valve, but the problems returned within a week because the pressure sensor was also compromised. Spending a bit more for the comprehensive fix definitely saved money in the long run. Have you noticed any change in fuel economy since the repair? My Polo went from terrible consumption back to normal once the system was working properly again.

The leak detection and fuel economy improvements have been significant since fixing those emission control components. My Fox now uses about 15% less fuel per tank compared to when the purge valve was malfunctioning. The check engine light has stayed off for over 2000km now. Having both the pressure sensor and purge valve replaced was definitely the right call, even though it cost a bit more upfront. The stalling issues are completely resolved and the engine runs smoothly at all speeds. For anyone else facing similar symptoms, make sure your repair shop checks both components rather than just replacing one. The pressure sensor and purge valve work together as part of the fuel tank ventilation system. In my case, one faulty part had damaged the other over time. Good point about the charcoal filter, I had mine inspected during the repair and it was still in decent condition. The shop recommended checking it again at the next major service to prevent any future emission control problems. Total repair cost of 320€ was money well spent considering how much better the car runs now. Thanks for sharing your similar experience, it helped confirm I was on the right track with the diagnosis.