BMW M4 Electrical Gremlins: Multiple Faults & Battery Issues

Hey there! I have some experience working on cars and had a very similar issue with my 2018 BMW M3 last year. Those symptoms sound exactly like what I dealt with, multiple warning lights, sluggish start, and electrical gremlins all over. Turned out my battery was severely discharged and needed replacement. Started getting these unusual errors in cold weather, and my local BMW specialist confirmed it with proper diagnostics. Total repair was around 290 Euro, including the new battery and labor. From what you're describing, it really sounds battery-related, but could you share: How old is your current battery? Are the issues more noticeable during cold starts? Do you take many short trips? This info would help confirm if you're facing the same problem I had. The M4 and M3 share a lot of electrical components, so I might be able to give you more specific advice.

Thanks for sharing your experience! My M4 currently has 184076 KM on the clock, and I'm actually having similar symptoms, especially during cold starts. My battery is still the original one from 2020, so your suggestion makes a lot of sense. I've been doing quite a few short trips lately which probably hasn't helped. Just had my routine service done last month but they didn't mention any battery issues. Think I'll get it checked out soon before I end up stranded somewhere! Did you notice any improvement in the general electrical system after your battery replacement?

Yeah, you definitely want to get that sorted soon! After I replaced my battery, it was like having a completely different car. All those unusual electrical gremlins disappeared instantly. I remember being amazed at how many issues were actually caused by just the battery being weak. The original batteries in these cars typically last around 4-5 years, so yours being from 2020 and having quite a few kilometers on it, plus those short trips... well, that's definitely pushing its limits. Those short trips are really tough on the battery because it never gets a chance to fully recharge. When I got my new battery, the first thing I noticed was how much stronger and faster the car started. No more of that sluggish cranking. All those warning lights and system errors completely vanished too. The auto start-stop feature started working properly again (it was super inconsistent before), and even the infotainment system became more responsive. Quick tip though, make sure whoever replaces it registers the new battery with the car's computer system. These BMWs need that to properly manage the charging system. My cousin skipped this step with his M4 and ended up having to go back to get it done right. Trust me, you'll be shocked at how many problems a fresh battery solves in these cars. Definitely worth getting it sorted before winter hits!

Thanks so much for all that detailed info! That's super helpful to know about the battery registration, definitely wouldn't have thought about that. I've actually noticed the auto start-stop being really inconsistent lately too, which makes even more sense now. Just booked an appointment with my mechanic for next week. Seems like I caught this issue just in time before it got worse. Really appreciate you sharing your experience, it's given me a lot more confidence about what the problem might be. The bit about the infotainment system is interesting too because mine's been a bit laggy lately. Amazing how one component can affect so many systems! Will make sure they do that registration you mentioned. The last thing I need is to have to make two trips to the shop! Thanks again for all your help, definitely made me feel better about the whole situation.