VW Up Start-Stop System Failures Causing Engine Stalls

Having moderate experience with VW vehicles, I faced a very similar issue with a 2015 VW Polo TSI that also had the idle stop feature. The symptoms were nearly identical, unusual engine stalling and start-stop system malfunctions. The starter motor would occasionally struggle, and the hybrid vehicle-like start-stop function became completely unreliable. After diagnostic testing, it turned out the battery was severely discharged and couldn't maintain proper voltage for the start-stop system. The workshop replaced the battery with a start-stop compatible model and performed a full system reset. Total cost was 290€, including programming. Since then, the engine start sequence and idle stop feature have worked flawlessly. To better assist with your situation, could you share: Current battery age, Mileage, Recent electrical issues or warnings, Whether you frequently make short trips, If the battery warning light ever appeared These details would help determine if your Up is experiencing the same battery-related problems that affected my Polo. Important to know: Using a standard battery instead of one specifically designed for vehicles with start-stop systems can cause these exact symptoms. The system requires a more robust battery to handle frequent engine starts.

My car has 15918km km and just had its annual service last month. The battery warning light never appeared before the start-stop system began acting up. The eco mode display still works, but the automatic restart feature fails intermittently. The current battery is the original one from 2014, so it might be time for a replacement. Thanks for mentioning the battery compatibility issue. I will check if my car battery is the correct start-stop system type. Having the original battery for 9 years could definitely explain these symptoms, especially considering the specific power requirements for the automatic restart function. Has anyone else needed to reset the system after installing a new battery?

Thanks for the additional details. Your situation sounds even more similar to what I experienced. My Polo had slightly higher mileage but showed the same symptoms when the original battery reached about 8-9 years. A system reset was definitely necessary after the battery replacement. The car battery needs to be properly registered with the vehicle computer for the start-stop system to function correctly. Without this reset, the automatic restart feature may work erratically or not at all. In my case, the workshop had to: 1. Install the new start-stop compatible battery 2. Reset the battery management system 3. Clear all stored error codes 4. Calibrate the idle stop parameters The procedure took about an hour, and the starter motor began working perfectly afterward. The investment in a proper battery and professional reset was worth it, considering how smoothly the system has worked since. Would strongly suggest not delaying the battery replacement, as continued use with a weak battery can potentially strain other electrical components. The hybrid vehicle-like stop-start cycles require consistent power delivery that aging batteries simply cannot provide.

Thank you for sharing those repair details. Your experience matches my situation perfectly, especially the part about battery age affecting the start-stop system performance. The original battery in my Up is definitely due for replacement after 9 years of service. I called my regular workshop and scheduled an appointment for next week. They confirmed they stock the correct start-stop compatible battery and can perform the full system reset procedure you described. The quoted price is 310€ including programming, which seems reasonable. Good to know about the reset being mandatory, I will make sure they complete all the steps you listed for the battery management system and error code clearing. Hopefully this will resolve my engine start issues and get the eco mode functioning normally again. Really appreciate everyone's input. I will update once the battery replacement is done to confirm if it fixed the unusual shutdown problem. Seems like proactive battery replacement around the 8-9 year mark is advisable for these start-stop equipped vehicles.