BMW 1 Series Coolant Leak Causing Multiple Warning Lights

Hey there! Had a similar situation with my 2017 BMW 2 Series last winter. Those symptoms sound very familiar, I experienced the same overheating and emergency mode issues. Turned out the DME control module had corroded connections, which messed with the cooling system sensors. Initial diagnosis at my garage wasn't clear, but the master tech found that water had gotten into the wiring harness connecting to the DME unit. The coolant leak in your case could be making this worse. They had to clean the connections, replace some damaged wiring, and reseal the whole assembly. Not a simple fix, took them two days to sort everything out, but definitely worth getting it done right. Make sure whoever works on it is certified for BMW electrical systems, as these control unit issues can be tricky to diagnose properly. For what it's worth, my car's been running perfectly since the repair, no more warning lights or overheating problems.

Thanks a lot for sharing your experience! That's super helpful and sounds exactly like what I'm dealing with. Really good to hear your car's running well after getting it fixed. I've been meaning to ask, do you remember roughly how much you ended up paying for the whole repair? Also, has everything stayed good since then, or have you noticed any other quirks popping up? Cheers!

Hey again! Glad to help! Actually, I just got my car back from the shop last week. You'll be happy to know my bill was way lower than I initially feared, just 95 € to fix a faulty cable connection to the control unit. The mechanic found water damage had messed with the wiring, just like in your case. Since the repair, everything's working perfectly, no more warning lights, no emergency mode, and the engine temp's staying exactly where it should be. It's such a relief! The communication error that was driving me crazy is completely gone now. My advice? Make sure you get a certified BMW tech to look at it. These electrical gremlins can be super tricky to diagnose if you don't know what you're looking for. But once they're fixed properly, they usually stay fixed. Trust me, it's worth getting it sorted properly, my car feels like new again. No other issues have popped up since the repair. Let me know how you get on with yours!

Just wanted to give you a quick update! Finally took my car to a certified BMW specialist and wow, what a difference! The tech found exactly what you described, water damage in the wiring harness. Got it all sorted last Thursday, new connections, proper sealing, the works. Bill came to about double what you paid, but honestly, it's worth every penny. Car's running like a dream now, no more warning lights, no leaks, and the temperature gauge is behaving perfectly. Such a relief after weeks of stress! Funny thing is, my regular mechanic had been suggesting all sorts of expensive repairs that probably wouldn't have fixed the actual problem. Really glad I reached out here and got your advice about finding a proper BMW specialist. Thanks again for all your help! You saved me from what could've been a much bigger headache and expense. Cheers!