Audi A3 Key Switch Failure Causing Random Stalls

Had the same starting issues with my Audi A4 2016. After several failed starts with the key turn, the diagnosis revealed multiple problems connected to the ignition system. The starter motor tested fine, but there was a failing ignition coil causing intermittent starting problems and rough running. The unusual shutoffs while driving pointed to a faulty crankshaft position sensor, which was interrupting signals to the car electronics. These symptoms often get misdiagnosed as simple battery or alternator issues, but the consistent dashboard lights typically rule those out. The fix required replacing two ignition coils and the crankshaft sensor. This was definitely a serious issue since unusual shutoffs pose a significant safety risk, especially at higher speeds. The repair needed specialized diagnostic equipment to properly identify the failing components. For the next mechanic visit, request a full diagnostic scan of the ignition system, specifically checking: Ignition coil resistance readings, Crankshaft position sensor signals, Wiring harness condition, Starting circuit voltage drop test Getting these specific areas checked will help avoid misdiagnosis and unnecessary parts replacement.

Thanks for sharing your experience with the A4. Just went through almost identical issues with my 2014 A3 last month. The symptoms match exactly, unreliable engine start when turning the key and unusual shutoffs. Like you mentioned, the faulty ignition coils were the main culprit in my case too. Mind sharing what the total repair cost was for your fix? My local shop ended up charging less than expected, but Im curious how costs compare. Also wondering if youve had any repeat issues since getting it fixed? The car ignition is working perfectly for me now, but always good to know what to watch out for long term.

Thanks for the follow-up. Since getting the repairs done on my A4, the car ignition system has worked flawlessly. The total repair came to 380 Euro, which included replacing two faulty ignition coils and the crankshaft sensor. There was also a blown fuse that needed replacement, adding 52 Euro to the bill. The ignition switch issues completely stopped after the fix. No more problems starting the car or unusual shutoffs while driving. The car electronics are all functioning normally now, and the ignition key turns smoothly every time. Its good to hear your A3 is running well after the repairs too. These ignition system problems can be tricky to diagnose, but once properly fixed, they typically stay resolved. Just keep an eye on any changes in how the engine starts or runs, early warning signs can help catch potential issues before they become serious.

Thanks everyone for the helpful replies. Finally got this sorted out properly. Took it to a different mechanic who actually knew what to look for after reading your suggestions. The diagnosis showed two bad ignition coils and a damaged wire harness causing the starting problems. Repair cost came to 320 Euro total including parts and labor. The starter motor and car electronics were tested and came back fine. What a relief to have the car starting reliably again! No more anxiety every time I turn the ignition key. The engine runs smooth now and no more sudden shutoffs. The mechanic also did a full system scan to make sure there weren't any other hidden issues. Really appreciate the specific advice about what to have checked. Saved me from another potential misdiagnosis and unnecessary parts replacement. Will definitely keep an eye out for any early warning signs, but so far everything is working perfectly.