BMW M2 Heat Issues: Faulty Water Valve or Something Else?

Hey! I have some experience working on BMWs. I dealt with a similar heating problem on my 2016 M3 last winter. Given your symptoms, it sounds really familiar. I took mine to my regular workshop since I'm not super confident with BMW's complex heating systems. Turned out it was indeed a faulty connection in the wiring harness going to the water valve control unit. They fixed the connection and replaced a worn plug, cost me around 95 Euro total. The heat's been working perfectly since then. Before I can give more specific advice, could you share: Which error code you're getting? Are there any other symptoms besides uneven heating? Have you noticed any changes in coolant level? Let me know these details and I might be able to help further. Sometimes these issues can be related to other components in the system.

Thanks for the detailed response! My car's been regularly serviced (last one at 82642 KM) and I've been getting error code P0597. The coolant level seems fine, but I've also noticed the temperature gauge acting a bit funny, fluctuating more than usual while driving. Haven't spotted any leaks or other obvious issues though. Interesting that you had a similar wiring issue with yours. The repair cost sounds reasonable if it's something similar. Did they need to keep your car long for the fix? I'm hoping it's just a connection problem like yours and not something more serious with the valve itself.

Hey again! Thanks for those extra details about your M2. You know, the P0597 code is exactly what my M3 was showing before I got it fixed. That code typically points to the thermostat heater control circuit, which makes sense with those temperature gauge fluctuations you're seeing. In my case, they only needed the car for about half a day, I dropped it off in the morning and picked it up after lunch. The wiring fix was pretty straightforward once they pinpointed the issue. Sounds like your symptoms are really similar to what I experienced, especially with those temperature fluctuations. Just a heads up though, while my issue was the wiring, sometimes these symptoms can also point to a failing thermostat. Mine's been running great since the wiring fix, but if they find your wiring is fine, you might want them to check the thermostat too. The thermostat replacement would cost more, but it's still not too bad considering it's a BMW. Given your regular maintenance record, I'd bet you're looking at something similar to what I had. Keep us posted on what they find, I'm curious to know if it turns out to be the same issue!

Thanks so much for all this information! It's really reassuring to hear that your repair was quick and relatively inexpensive. After what you've shared about the P0597 code and those similar symptoms, I'm feeling more optimistic about getting this sorted. I've actually just booked my car in for tomorrow morning, figured it's better to get it checked sooner rather than later, especially with your insight about the thermostat possibility. Really appreciate you taking the time to share your experience. I'll definitely keep you posted on what they find, hopefully it'll just be that wiring issue like yours. Half a day without the car isn't bad at all. Fingers crossed it's as straightforward as your repair was! And if it does turn out to be the thermostat, at least I'm prepared for that possibility now. Thanks again for all your help!