VW Transporter Starting System Failure Causes Headaches

Had nearly identical issues with my 2012 VW Tiguan. The symptoms match what I experienced, intermittent starting problems and engine cutting out out of nowhere. While the ignition key turned fine, the ignition switch assembly was failing internally, causing inconsistent electrical contact. The root cause was a worn ignition switch mechanism, which created unreliable connections between vital starting circuits. This affected both the initial start and maintaining proper power during operation. The car electronics seemed normal because the switch would make enough contact to power the dash, but not enough for reliable engine operation. The fix required replacing the complete ignition switch assembly. This was definitely a serious issue since it affected basic vehicle operation and safety. The failing switch could have left me stranded at any time. Key signs it was the ignition switch: Engine would sometimes crank but not start, Unusual stalling while driving, Rough running when the switch made partial contact, No warning lights or obvious electrical issues Getting the proper diagnosis is crucial, the symptoms can mimic fuel system or sensor problems. A qualified technician should test the ignition switch circuit specifically, not just run general diagnostics.

Thanks for the detailed writeup about the ignition switch problem. Your description matches exactly what I went through with my Transporter last winter. The starter motor behaved so erratically, sometimes cranking fine and other times completely dead despite the dashboard lights working normally. Did you track the total repair cost for the ignition switch replacement? Also wondering if any other issues popped up after fixing the switch, since sometimes when the key turn is inconsistent it can strain other components in the starting system. My mechanic initially misdiagnosed it as a fuel pump problem and I wasted money chasing the wrong issue. Would be helpful to know the cost to budget for the proper fix.

After replacing the ignition switch the starting problems disappeared completely. The entire repair cost came to 52€ for a blown fuse that was discovered during the switch replacement. The starter motor now engages smoothly every time with normal key turn function. No secondary issues developed after the fix. The erratic starting behavior and rough running were entirely due to the faulty switch causing inconsistent power delivery. The dashboard lights worked normally throughout because they needed less current than the starting circuit. Getting an accurate diagnosis early saved both time and money, much better than my previous mechanic who chased phantom fuel system problems. When the ignition switch fails it can definitely mislead troubleshooting since the symptoms affect multiple systems. The consistent starting performance since the repair confirms it was the right fix. No more worrying about unusual stalling or whether the engine will start when turning the key.

I finally got my Transporter properly fixed last week after dealing with all those starting problems. Took it to a different mechanic who actually listened to the symptoms and tested the ignition system properly. Just as suggested, it turned out to be a faulty ignition switch causing all the trouble. The repair cost came to 280€ including parts and labor. The starter motor now engages perfectly every time I turn the key. No more unusual stalling or rough running, it starts and runs like new. The ignition coil and other components checked out fine, so no additional repairs were needed. Such a relief to have it running properly again. Really glad I got a second opinion instead of throwing more money at incorrect diagnoses. The car starts reliably now and the engine runs smooth. Should have checked the ignition switch first instead of replacing unnecessary parts. Looking back, an experienced mechanic would have caught this sooner by testing the ignition system thoroughly. At least now I know what to watch for if similar starting problems ever come up again.