VW Tiguan Start-Stop Failure Causes Random Stalling

I had a similar issue with my VW Golf 2.0 TDI from 2011. As someone with moderate experience working on VW diesels, I can confirm this is often related to the start-stop system and battery health. The symptoms were nearly identical, unusual stalling, start-stop system malfunctioning, and engine warning lights. My starter motor was fine, but the diagnostic revealed a heavily discharged battery that couldn't properly support the idle stop functionality. The workshop found the original battery had degraded significantly, affecting the eco mode and start-stop features. They replaced it with a higher capacity battery specifically designed for vehicles with start-stop systems, which solved all issues. Total cost was 290€ including diagnostics and installation. Before proceeding with repairs, could you share: Current battery age, Whether you make mostly short or long trips, If the problems started gradually or suddenly, What error codes are showing These details would help determine if your situation matches what I experienced. The start-stop system is quite sensitive to battery condition, and proper diagnosis is crucial for an effective fix.

Last service was at 54000km, about 2 months ago. You are right about the battery condition affecting the start-stop system. After reading your reply, I checked my car battery and noticed its manufacturing date, it is the original one from 2009. The automatic restart issues started appearing gradually over the last month. I mainly do short trips under 15 minutes, which probably contributed to the battery drain. The car battery barely manages to provide enough power for the eco mode features now. The error codes point to low voltage during engine start sequences. Will get the battery replaced with a start-stop compatible unit. Hope this resolves the stalling issues like in your case.

Thanks for the follow-up details. Your driving pattern with frequent short trips definitely impacts the car battery life, especially with idle stop systems that require more power. The original battery from 2009 has done well to last this long, but its clearly struggling now with the demands of the start-stop system. Those 15-minute journeys rarely allow enough time for proper battery charging, which is crucial for reliable automatic restart functionality. After replacing my battery, not only did the engine start issues resolve, but I noticed the start-stop system became much more responsive. One tip: when getting the new car battery, ensure its specifically rated for start-stop systems, as they need higher cycling capacity. The starter motor takes more strain with frequent auto start sequences. The error codes pointing to low voltage during engine start confirm what I experienced. Once the new battery was installed, all warning lights cleared and the idle stop feature worked flawlessly again. Your situation matches my experience exactly, same symptoms, same root cause. A new battery should sort out both the stalling and automatic restart problems. Just make sure to clear the error memory after installation.

Thanks for sharing those insights about the battery. The original 2009 battery definitely needs replacement, especially given my short-trip driving pattern that impacts the charging cycles. The error codes showing low voltage during start sequences make perfect sense now. Looking at the symptoms, engine stalling, automatic restart failures, and idle stop system issues, it all points to insufficient battery power. Will schedule the battery replacement this week and make sure to get one specifically designed for cars with start-stop systems. Your experience with the Golf gives me confidence this should resolve the unusual stalling problems. Good point about clearing the error codes after installation. Will ask the workshop to do that along with the battery swap. The symptoms match your case exactly, so hoping for similar positive results once the new battery is powering the starter motor properly. Will update on the outcome after getting this sorted. Thanks for helping pinpoint the likely cause and sharing the repair details.