BMW 2 Series ECU Power Failure: No-Start Mystery

Hi! I have some experience working on BMWs and went through something very similar with my 2018 BMW 3 Series last year. The symptoms you're describing sound exactly like what I experienced. My car also wouldn't start and showed ECU voltage issues. Took it to my trusted workshop and it turned out to be a faulty wiring connection to the ECU, specifically some corroded terminals that weren't making proper contact. The repair cost me around 95 Euro, which included cleaning the connections and replacing a damaged cable. Before I can give more specific advice, could you share: Have you noticed any other electrical issues recently? Does the issue happen consistently or intermittently? Are you getting any other warning lights on the dash? BTW, I also own a BMW 5 Series and these cars can be sensitive to electrical gremlins, but they're usually straightforward fixes once properly diagnosed.

Thanks for your detailed response! I just had my latest service done but this issue started right after. Given I've only done 20112 KM in my 2020 2 Series, this is pretty frustrating. Haven't noticed any other electrical issues until now, and it's happening every single time I try to start the car. No other warning lights except the standard ones when the car isn't running. I'm really hoping it's just a connection issue like you had and not something more serious with the ECU itself. Did your car show any warning signs before it completely failed to start?

Hey again! Thanks for the follow-up. Interesting that this started right after your service, that actually rings a bell because my issue also cropped up after some routine maintenance. In my 3 Series, there weren't any warning signs before the complete failure, which sounds similar to your situation. It just decided to quit one morning! Since you mentioned it's happening consistently since the service, I'd definitely suggest getting back to wherever did your maintenance. From my experience, sometimes these issues can pop up if connections weren't properly secured after service work. In my case, turns out some moisture had gotten into the connection during a wash, and combined with a slightly loose terminal from previous work, it created the perfect storm for electrical problems. The good news is that since your 2 Series is relatively new with low mileage, it's unlikely to be a major ECU failure. Mine was a simple fix once they found the actual cause, and I've had zero issues since then. If you're getting the same symptoms I had (complete electrical failure to ECU), I'd bet it's connection-related rather than a fault in the unit itself. Quick tip from what I learned: don't let them jump straight to replacing the ECU without thoroughly checking all connections first. Could save you a bunch of money!

Thanks so much for sharing your experience, that's actually really reassuring! You're right, I should definitely head back to the service center first since the timing is too coincidental. I'll make sure they check all the connections thoroughly before jumping to any expensive conclusions about the ECU itself. Really appreciate you taking the time to walk me through your similar experience with your 3 Series. Knowing it was a straightforward fix in your case makes me feel much better about getting this sorted. I'll update you once I get it checked out, fingers crossed it's just a loose connection like yours was! Thanks again for all the helpful advice.