BMW 2 Series ECU failure symptoms & repair costs

Hey there! I had very similar issues with my 2016 BMW 1 Series last year. Initially thought it was the ECU too, but it turned out to be a defective main relay. The symptoms matched exactly what you're describing, slow starts, power loss, and unusual electrical system shutdowns. Took it to my mechanic when it started cutting out while driving, which was pretty scary. They diagnosed it after running some comprehensive tests. The main relay repair isn't typically a complex job, but it's critical because it controls power distribution to various electrical components including the ECU. Mine took about half a day to fix, and honestly, it wasn't as serious as I initially feared. The car has been running perfectly since then, no more unusual shutdowns or power issues. Before you jump to ECU conclusions, have a qualified mechanic check the main relay and electrical system. Could save you from an unnecessary ECU replacement.

Thanks for sharing your experience with the main relay issue! That's really helpful information. Did you happen to remember roughly how much the repair set you back? Just trying to get an idea of costs in case I'm dealing with something similar. Also curious if you've had any other electrical gremlins pop up since getting it fixed?

Hey again! Happy to give you an update! After my original post, I actually had this exact issue fixed, you'll be glad to know it was indeed the main relay that was causing all the trouble. The total repair came to 120 € at my mechanic's, and honestly, it was money well spent. Since getting it sorted out, my BMW has been running like a dream. The ECU is working perfectly now, no more of those annoying slow starts or power drops that were driving me crazy before. It's been several months, and I haven't had a single electrical gremlin pop up. Just to set your mind at ease, once they replace that faulty relay, the car feels like new again. The unusual system shutdowns completely stopped, and the engine response is back to its usual snappy self. Trust me, it's such a relief not having to worry every time I turn the key! Let me know how it goes when you get yours checked out. Fingers crossed it's the same straightforward fix for you!

Thanks so much for the detailed follow-up! I actually just got back from the mechanic and you won't believe it, it was exactly what you described! The main relay was shot, and they fixed it for about the same cost you mentioned. Had to find a different mechanic though, since my old one kept insisting it was the ECU. This new guy diagnosed it right away. The car's running perfectly now, starts up instantly and all systems are working great. Such a relief it wasn't something more serious! Funny how these things work out, was stressing about potentially spending thousands on an ECU replacement, and it ended up being a relatively simple fix. The mechanic even showed me the old relay and explained how it was causing all those problems. Really appreciate you sharing your experience, helped me avoid an unnecessary expensive repair. My BMW's back to its old self now, and my wallet's still intact!