BMW 2 Series Won't Start: Cranking Issues & Dim Lights

Hey there! I've got some experience with BMWs, had a similar issue with my 2016 BMW 1 Series last year. The symptoms you're describing sound exactly like what I dealt with. Turned out, it wasn't actually the starter, it was a faulty battery that got damaged because of a defective alternator. The workshop fixed it under warranty since the alternator failure caused the battery damage. I was lucky because my regular mechanic, who specializes in BMWs, spotted the real issue right away. They replaced both parts, and I haven't had any problems since. Could you share which engine variant you have in your 2 Series and what error code you're getting? That would help narrow things down. Also, have you noticed any other electrical issues before this started happening?

Hey, thanks for sharing your experience! I've got the gasoline engine variant and just had my last service completed recently. Currently at 39275 KM. My symptoms do sound very similar to what you experienced. Actually, now that you mention electrical issues, I've noticed my power windows have been a bit sluggish lately, which I didn't think was related at first. Have you or anyone else tried using a multimeter to test the battery voltage before going straight to the workshop? I'm wondering if I could diagnose this myself before taking it in. The error code I'm getting is P0562, which from what I understand is related to system voltage. Really appreciate the help troubleshooting this!

Hey again! Yeah, I totally remember my experience with this, and those symptoms you're describing are ringing some serious bells. I actually did try using a multimeter before taking it to the workshop, good thinking there! Got a reading of around 11.8V with the engine off, which was definitely lower than the normal 12.6V you want to see. When I tried starting the car, it dropped below 10V, which was a clear red flag. That P0562 code is exactly what I got too, it's definitely a voltage issue. The sluggish power windows are another telltale sign. I ignored those kinds of small electrical quirks at first, and honestly, I wish I hadn't because they were early warning signs. Since you're at 39275 KM, it's about the same mileage where my issues started popping up. The alternator was putting out inconsistent voltage, which basically killed my battery over time. Looking back, I should've checked the alternator output voltage while the engine was running, that would've shown the problem earlier. One quick test you can do: if you have access to a voltmeter, check the voltage at the battery with the engine running. It should be between 13.5-14.5V. Mine was fluctuating wildly, which was a dead giveaway for the alternator issue.

Thanks so much for the detailed advice! That's super helpful, especially about the voltage readings. I actually have a multimeter in my garage, so I'll definitely try checking those numbers you mentioned. Just tested it now, getting 11.9V with the engine off and it drops to 9.8V when trying to start, which sounds pretty similar to what you experienced. When I tried checking the voltage with the engine running, it was bouncing between 12.2V and 13.8V, which doesn't seem normal based on what you've said. Guess my alternator might be the culprit too. At least now I won't be going into the workshop blind, I can tell them exactly what I've tested and found. You've saved me a lot of headache and probably some money too by helping me pinpoint the likely issue. I'll get it booked in tomorrow and have them check both the alternator and battery. Better to sort it now before I end up stranded somewhere! Really appreciate you taking the time to help me diagnose this!