BMW 4 Series Start-Stop Failure & Engine Shutdowns

Hey there! I have some experience with cars and had a very similar issue with my 2020 BMW 3 Series diesel (love those BMWs!). The symptoms you're describing match exactly what I went through. After taking it to my regular workshop, they diagnosed a heavily discharged battery that was on its way out. Had it replaced and everything went back to normal, start-stop system, unusual shutdowns, warning lights, the whole deal. The fix cost me 290 Euro, parts and labor included. Before you head to the workshop, could you share what model variant of the 4 Series you have and how many miles are on it? Also, have you noticed any other electrical issues, like dim lights or slow cranking? This info would help me tell if you're dealing with the same problem. Definitely get those error codes read, they're super helpful for narrowing down the issue. Let me know and I'll try to help more!

Thanks for sharing your experience! I've got the 2022 4 Series with 23093 KM on the clock, and just like you mentioned, I've noticed the slow cranking recently. Actually, come to think of it, my headlights have seemed a bit dimmer lately too, especially at night. That's really helpful about the battery issue, makes total sense with all these symptoms matching up. I'll definitely get those error codes read before heading to the workshop. Just hoping it's as straightforward as a battery replacement and nothing more serious with the electrical system. Did you have any warning signs before your battery completely gave out? Would be great to know what to watch out for in the future.

Hey again! Thanks for the follow-up. Yeah, looking at your mileage and those symptoms, it's definitely sounding more and more like what I dealt with. Those dimmed headlights and slow cranking are exactly what I experienced before things got worse. With my 3 Series, I actually had a few warning signs before the battery completely gave up. First, it was just occasional slow starts in the morning, but I brushed it off thinking it was just the cold weather. Then the start-stop system began acting up, sometimes working, sometimes not. The headlights getting dimmer was actually the last sign before everything started going haywire. The funny thing is, I initially thought it might be something more serious (and expensive!) with the electrical system too. Was pretty relieved when it turned out to be just the battery. After the replacement, it was like having a new car again, all those little issues just disappeared. Quick tip from my experience: once you get the new battery, make sure they register/code it properly with the car's computer system. BMW's can be pretty picky about that. Mine wasn't done initially, and it caused some weird behavior until they sorted it out. Keep us posted on what those error codes say! I'm betting they'll point to battery issues too.

Thanks so much for all the detailed info! It's really reassuring to hear that you went through the same thing and it was just a battery issue. Those warning signs you mentioned are spot on, I've definitely been ignoring the slow morning starts too, thinking it was just normal in colder weather. Really appreciate the tip about getting the battery properly coded. I had no idea that was even a thing with BMWs! I'll make sure to mention that specifically when I take it in. Going to get those error codes read tomorrow and will probably book it in for service next week. You've saved me a lot of worry, I was starting to imagine all sorts of expensive repairs! Will definitely keep an eye on those warning signs you mentioned for the future too. Thanks again for all your help!