BMW X3 Battery Issues: Sensor or Something More Serious?

Hi there! I have some experience with cars and had a very similar issue with my 2015 BMW X5 last year. The symptoms were exactly the same as yours, battery warning, slow cranking, and electrical gremlins all over. My trusted workshop diagnosed it as a faulty battery sensor, which was causing incorrect readings and draining the battery. The repair cost me 315 Euro including parts and labor. After replacing the sensor, all problems disappeared completely. Before jumping to conclusions though, could you share some more details? Have you had any recent electrical work done? Also, when was the last time you replaced the battery? The symptoms could be similar with other BMW models like the X1, so knowing these details would help pinpoint the issue better.

Thanks for your input! I'm at 54756 KM since my latest service. The battery is actually original from 2013, so that's probably a major red flag right there. Haven't had any electrical work done recently, but I'm starting to think it might be more than just the sensor given the battery age. Did your workshop do any additional testing before replacing the sensor to rule out alternator issues? Just trying to get an idea of what diagnostic steps I should expect.

Hey again! Since you asked about the diagnostic steps, yes, my workshop did quite thorough testing before zeroing in on the sensor. They actually first checked the alternator output and did a full electrical system scan. In my case, the alternator was working perfectly fine, generating the correct voltage. But I've got to be honest, your battery being the original from 2013 is definitely setting off alarm bells! Mine was about 5 years old when I had these issues, and that was already pushing it. These luxury cars are pretty demanding on batteries, especially with all the electronic systems they run. Looking back at my experience, I'd suggest getting both the battery and sensor checked. When the workshop diagnosed mine, they found that while the sensor was the main culprit, the battery itself was also showing signs of wear. I ended up getting both replaced just to be safe, figured it was better than having to deal with it again in a few months. The good news is, after sorting both issues out, my X5 has been running like a charm. No more warning lights, strong starts every time, and all electrical systems working perfectly. Given what you've described, I'd bet you're looking at a similar solution. Let me know what you find out, I'm curious to hear if your experience mirrors mine!

Thanks so much for the detailed follow-up! You've definitely convinced me to get both components checked out. My gut was telling me the original battery might be part of the problem, and hearing about your experience pretty much confirms it. I'll schedule an appointment with my workshop and make sure they do that full system diagnostic you mentioned, seems like the smart way to go rather than just replacing parts and hoping for the best. Actually feeling a bit relieved now knowing this is a common issue with a clear solution. I was worried it might be something more serious or complicated. Will probably follow your lead and just replace both the battery and sensor while I'm at it. Like you said, better to handle it all at once than deal with repeated issues. Really appreciate you sharing your repair experience, it's exactly the kind of real-world insight I was hoping for. I'll give an update once I get it sorted out!