BMW X2 Water Sensor Issue Causing Rough Idle, Help Needed

Hi there! I have some experience working on cars and had a similar issue with my 2017 BMW X1 last year. That sensor problem can be really annoying! When it happened to me, I took it to my regular workshop since I didn't want to risk messing with electrical components myself. Turned out the wiring harness connecting to the water sensor had corroded and some pins were loose. The mechanic replaced the connector and rewired it properly. Total cost was around 95 Euro for parts and labor. Since you have a slightly newer X2, the setup might be a bit different. Could you share more details about your mileage and whether you've had any other electrical issues recently? Also, does the rough idle happen more when the engine is cold or after it's warmed up? This would help pinpoint if we're dealing with the exact same problem. By the way, these sensor issues seem pretty common in the X series BMWs, seen quite a few posts about it in various forums.

Hey thanks for your detailed response! My X2 has 80952 KM on the clock and just had its service last month. The rough idle actually happens more when the engine is warm, especially after driving for about 20-30 minutes. Haven't noticed any other electrical issues so far, which makes this pretty puzzling. Did your repair completely solve the problem, or did you have any recurring issues afterward? Really hoping it's just the wiring harness like in your case, rather than something more serious.

Hey again! Thanks for those extra details about your X2. When you mentioned the rough idle happening after 20-30 minutes, that actually sounds really similar to what I experienced with my X1. In my case, the initial wiring harness repair did fix the problem for about 3 months, but then it started acting up again. Turned out there was a bit more to it, the water sensor itself was actually damaged too, not just the wiring. Had to go back and get the entire sensor assembly replaced, which was more expensive (around 280 Euro total), but that finally sorted it out permanently. Since your symptoms are so similar, and you're also driving a newer X series, I'd recommend asking your mechanic to check both the wiring AND the sensor itself. Sometimes these sensors can get damaged gradually, and the wiring issues are just a symptom of a bigger problem. Just curious, when your engine gets rough, have you noticed any changes in the temperature gauge? With mine, it would fluctuate slightly when the problem was at its worst. Might be worth keeping an eye on that. The good news is that once it's properly fixed, it should be fine. Haven't had any issues with mine for over a year now.

Thanks so much for sharing your experience, this is super helpful! Actually, now that you mention it, I have noticed some small temperature fluctuations on the gauge, though I didn't think much of it at first. That's really interesting about the sensor itself being damaged in your case. I'll definitely make sure to have both the wiring and the sensor checked out when I take it in. Don't want to end up having to make two trips like you did! Going to book it in at the workshop tomorrow and will specifically mention checking both components. The cost doesn't sound too bad either, even if I need the full sensor replacement. Really appreciate you taking the time to share all these details, it's given me a much better idea of what to expect. Will definitely update the forum once I get it sorted out, in case anyone else runs into the same issue with their X series.