BMW X1 Terminal 15 Voltage Issue Preventing Engine Start

Hey there! I have some experience with BMWs and had a similar issue with my 2012 BMW X3 a while back. Not a pro mechanic but I've dealt with my fair share of car troubles. The Terminal 15 voltage problem you're describing sounds exactly like what I faced. Mine turned out to be a faulty connection in the wiring harness near the ignition switch. Took it to my regular workshop, and they traced it down to a damaged cable and corroded plug connector. Total repair cost me 95 Euro to replace and fix the connection. Before you go further, could you let me know: Have you noticed any intermittent starting issues before this? Does your key fob work normally? Any recent battery-related problems? This info would help me better understand if you're dealing with the same thing I had on my X3. These issues can sometimes be related to different components on different models, even within the BMW family.

Thanks for the detailed response! My X1 has been super reliable up until now (19027 KM on the clock, last serviced 3 months ago). Actually, yes, I've noticed it being a bit sluggish to start for the past few weeks, but I just brushed it off. The key fob works perfectly fine, so that's not the issue. No battery problems that I'm aware of, though I haven't had it checked recently. The wiring harness issue you mentioned sounds pretty similar to what I might be dealing with. Did you notice any warning lights or weird electrical behavior before your car completely failed to start? At this point, I'm thinking I should probably get it checked by a professional rather than trying to fix it myself, but I'd love to hear more about what signs you noticed leading up to the complete failure.

Hey again! Thanks for the extra details about your X1. When you mentioned the sluggish starting, that really rang a bell for me, it was exactly the same with my X3 before things went south. Yeah, before my car completely gave up, I noticed a few things that might help you: The dashboard lights would sometimes flicker ever so slightly when starting the car, especially on cold mornings. Also, occasionally my radio would reset itself, super annoying when you're in the middle of your favorite song! These were the warning signs I totally ignored (not my brightest moment). The thing about these Terminal 15 issues is they're sneaky, they start small and get progressively worse. Your mileage is actually pretty low, which makes me even more convinced it's probably a wiring issue like mine was. The fact that your key fob works fine is good news, at least we can rule that out. Given your description, I'd definitely recommend getting it checked by a pro. When mine failed completely, I actually tried poking around myself first and honestly just made things more complicated for the mechanic (oops). These BMW electrical systems are pretty complex, and while the fix might be simple like in my case, finding the exact problem spot requires proper diagnostic tools. Just a heads up, better get it sorted soon. Mine went from "a bit sluggish" to "completely dead" in about two weeks. Let me know what you find out, really curious if it turns out to be the same issue!

Thanks so much for all this information, it's incredibly helpful! Those symptoms you described with the flickering dashboard and radio resets... I've actually noticed similar things happening but didn't connect the dots until now. It's almost scary how similar our issues sound. I'll definitely take your advice and get it checked out ASAP. Really don't want to end up stranded somewhere with a dead car. I've already called a BMW specialist mechanic and booked it in for tomorrow morning. You're right about not trying to fix it myself, I was tempted to start poking around under the hood, but after what you've said, I'll leave it to the professionals. Seriously appreciate you taking the time to share your experience. Having a rough idea of what might be wrong and what to expect really helps ease my mind about the whole situation. I'll update the thread once I get the diagnosis back from the mechanic, might help someone else with the same issue down the line!