VW Golf Diesel Stop-Start System Fails During Driving

Last month I experienced similar symptoms with my 2011 VW Passat TDI. The automatic restart system was failing intermittently, especially during cold starts. The diagnostic revealed two main issues: The first problem was a heavily discharged car battery that could no longer maintain sufficient voltage for the start-stop system. These systems require a robust battery performance to handle frequent restarts. When battery capacity drops below a certain threshold, the automatic restart feature becomes unreliable. The second issue involved corroded battery terminals affecting power distribution. The battery management system was receiving incorrect voltage readings, causing the start-stop system to malfunction. The fix required: Full battery capacity test, Replacement of the original battery with a start-stop specific unit, Cleaning and reconditioning of battery terminals, Battery management system reset This was a serious repair since a failing battery can eventually prevent the car from starting completely. The start-stop system automatically deactivates when it detects battery issues to prevent getting stranded. Given the age and mileage of your Golf, its likely facing similar battery degradation. These symptoms typically appear when the original battery reaches end of life or when the charging system isnt maintaining proper voltage.

Thanks for sharing your Passat experience. I had almost the same engine stalling issues with my Golf last summer. The starter motor would occasionally fail to engage after the auto stop, leaving me stuck at traffic lights. Really nerve-wracking. My mechanic also found the car battery was the main culprit, along with a faulty voltage sensor that was confusing the start-stop system. Getting both fixed solved it completely. Have you had any other problems since the repair? Just curious about the long-term reliability. Also, would you mind sharing what the total repair cost was? Might help others budget for similar issues with their VWs.

Since getting the repairs done six months ago, my Passat start-stop system has been working flawlessly. The engine stalling issues disappeared completely after replacing the degraded battery and fixing the voltage sensor. The car starts smoothly every time now, even in eco mode. The total cost came to 290€ which included: New start-stop compatible battery, Voltage sensor replacement, System diagnostics, Labor costs The battery issue was definitely worth fixing promptly, these problems tend to get worse if left unchecked and can lead to more expensive repairs. The investment has paid off with reliable performance and no more worrying about getting stuck at intersections. The start-stop system now engages properly and the battery maintains consistent power levels. Regular voltage checks show everything is operating within normal parameters. It seems the original battery just couldnt handle the demands of frequent auto start-stop cycling anymore.

Thanks everyone for the helpful replies. Finally took my Golf to a new mechanic last week after the engine stalling got worse. Turned out to be exactly what you described, a failing battery causing the start-stop system to malfunction. The mechanic found the original battery was only holding 60% charge capacity. He also discovered some corrosion on the terminals that was messing with the voltage readings. The total bill came to 320€ for a new enhanced battery, terminal cleaning, and diagnostic work. After the repair, the automatic restart is working perfectly again. No more unusual shutdowns or failed starts at traffic lights. The eco mode and start-stop system engage smoothly now. Such a relief not having to worry about getting stranded anymore. Really glad I got it sorted before winter. The mechanic explained these battery issues tend to get worse in cold weather, which could have left me with bigger problems. Appreciate all the advice that helped me understand what was going on with my car.