Audi A1 Idle Stall Linked to Fuel Tank Vent System

Having some experience with engine management systems, I faced a similar issue with my 2019 Audi A3. The symptoms were nearly identical, check engine light illuminating and rough idle conditions. The problem turned out to be a defective activated charcoal filter, which is part of the emission control system. The faulty filter was disrupting proper air flow and causing system failure messages. After diagnosis, the repair involved replacing the charcoal filter and testing the purge valve function. Total cost was 275 Euro including parts and labor. The leak detection test performed by the workshop confirmed that the charcoal filter was not properly filtering fuel vapors, leading to incorrect readings in the emission control system. Once replaced, the idle problems disappeared completely and the check engine light has stayed off. To provide more specific guidance for your A1: What engine size do you have? Are you noticing any fuel smell? Does the problem occur more frequently after refueling? Have you scanned for specific error codes? These details would help determine if your issue matches what I experienced and whether the same repair approach would be appropriate.

Having some experience with engine management systems, I faced a similar issue with my 2019 Audi A3. The symptoms were nearly identical, check engine light illuminating and rough idle conditions. The problem turned out to be a defective activated charcoal filter, which is part of the emission control system. The faulty filter was disrupting proper air flow and causing system failure messages. After diagnosis, the repair involved replacing the charcoal filter and testing the purge valve function. Total cost was 275 Euro including parts and labor. The leak detection test performed by the workshop confirmed that the charcoal filter was not properly filtering fuel vapors, leading to incorrect readings in the emission control system. Once replaced, the idle problems disappeared completely and the check engine light has stayed off. To provide more specific guidance for your A1: What engine size do you have? Are you noticing any fuel smell? Does the problem occur more frequently after refueling? Have you scanned for specific error codes? These details would help determine if your issue matches what I experienced and whether the same repair approach would be appropriate.

Thanks for the detailed troubleshooting suggestions. For my A1 with 19173 KM, the EVAP system problems started right after the latest service. Looking into your questions: mine is a 1.0L TFSI engine, and yes, there is a faint fuel smell particularly after filling up. Have not scanned for codes yet but planning to check that next. The activated charcoal filter route makes sense given the symptoms. Similar to what you described, the stalling mostly happens at idle and gets worse when the engine is warm. Did you notice if replacing the filter also improved fuel efficiency? Currently monitoring my consumption since the issues started.

Thanks for the detailed troubleshooting suggestions. For my A1 with 19173 KM, the EVAP system problems started right after the latest service. Looking into your questions: mine is a 1.0L TFSI engine, and yes, there is a faint fuel smell particularly after filling up. Have not scanned for codes yet but planning to check that next. The activated charcoal filter route makes sense given the symptoms. Similar to what you described, the stalling mostly happens at idle and gets worse when the engine is warm. Did you notice if replacing the filter also improved fuel efficiency? Currently monitoring my consumption since the issues started.

Thanks for those additional details. The similarities are striking, my A3 also showed these symptoms shortly after routine maintenance, which makes me more confident we are dealing with the same issue. After replacing the activated charcoal filter, I noticed about 8% improvement in fuel efficiency. The link between poor air flow and increased fuel consumption became clear once the system was working properly again. One thing I did not mention earlier, before replacing the filter, I also noticed the stalling would get notably worse in humid conditions. The leak detection system would trigger the check engine light more frequently during these times. Once the new filter was installed, these weather-related issues completely disappeared. For your 1.0L TFSI, definitely get those codes read before proceeding. While our symptoms match, having the specific error codes will confirm if the charcoal filter is indeed the culprit. The fuel smell after filling up is a telling sign though, identical to what I experienced. Make sure the workshop checks the entire EVAP system during repair, not just the filter. In my case, they also found a small crack in one of the connecting hoses that needed attention.

Thanks for those additional details. The similarities are striking, my A3 also showed these symptoms shortly after routine maintenance, which makes me more confident we are dealing with the same issue. After replacing the activated charcoal filter, I noticed about 8% improvement in fuel efficiency. The link between poor air flow and increased fuel consumption became clear once the system was working properly again. One thing I did not mention earlier, before replacing the filter, I also noticed the stalling would get notably worse in humid conditions. The leak detection system would trigger the check engine light more frequently during these times. Once the new filter was installed, these weather-related issues completely disappeared. For your 1.0L TFSI, definitely get those codes read before proceeding. While our symptoms match, having the specific error codes will confirm if the charcoal filter is indeed the culprit. The fuel smell after filling up is a telling sign though, identical to what I experienced. Make sure the workshop checks the entire EVAP system during repair, not just the filter. In my case, they also found a small crack in one of the connecting hoses that needed attention.

Thanks for the thorough follow-up and yes, this definitely sounds like a similar problem, particularly the EVAP system connection to my refueling issues. The pressure sensor readings will be important to check next. Really appreciate the tip about checking the entire emission control system and not just focusing on the charcoal filter. Will get those error codes pulled tomorrow and ensure they inspect the connecting hoses during the repair. The fact that the fuel efficiency improved after your fix gives me hope this will resolve my consumption issues too. The weather connection you mentioned is interesting, now that you bring it up, the leak detection warnings do seem more frequent on damp mornings. Will add this detail when discussing with the workshop. Knowing the total repair cost in your case helps set realistic expectations too. Time to schedule that diagnostic session and get this sorted.

Thanks for the thorough follow-up and yes, this definitely sounds like a similar problem, particularly the EVAP system connection to my refueling issues. The pressure sensor readings will be important to check next. Really appreciate the tip about checking the entire emission control system and not just focusing on the charcoal filter. Will get those error codes pulled tomorrow and ensure they inspect the connecting hoses during the repair. The fact that the fuel efficiency improved after your fix gives me hope this will resolve my consumption issues too. The weather connection you mentioned is interesting, now that you bring it up, the leak detection warnings do seem more frequent on damp mornings. Will add this detail when discussing with the workshop. Knowing the total repair cost in your case helps set realistic expectations too. Time to schedule that diagnostic session and get this sorted.