BMW Water Sensor Issue: Rough Engine & Warning Light

I had a similar issue with my 2008 BMW 528i last winter. The check engine light came on, and the engine was running quite rough, especially during cold starts. The diagnostic pointed to a faulty water/coolant level sensor connection. Got it checked at the garage, and it turned out the cable connecting to the sensor was corroded and had a loose connection. The mechanic cleaned the connector pins and replaced the wiring harness for that section. The whole thing wasn't too serious, more of an annoyance than a major problem. My experience wasn't bad, though the diagnostic took longer than expected because they had to rule out other potential issues first. In your case, I'd suggest getting it looked at soon since rough running can lead to bigger problems if left unchecked. Make sure whoever checks it is familiar with BMW electrical systems, as these sensors can be tricky to diagnose correctly.

Thanks for sharing your experience! That's pretty much exactly what I'm dealing with right now. I'm relieved to hear it wasn't something more serious in your case. Just wondering, do you remember roughly how much you ended up paying for the repair? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up? I'm trying to get an idea of what I might be looking at cost-wise and whether I should be prepared for any follow-up problems.

Hey there! Just wanted to follow up, I'm happy to report that after getting it fixed, my BMW has been running like a charm! The total repair came to 95€, which covered fixing the cable and plug connection to the water sensor. The mechanic found the connection was indeed faulty, just as they suspected. I know you were worried about potential follow-up issues, but I can honestly say I haven't had a single problem since the repair. The check engine light stayed off, and that rough running completely disappeared. It's been such a relief, especially since I was initially worried it might be something more serious (and expensive!). Trust me, once you get it sorted, you'll probably find it's the same straightforward fix. These sensor issues can seem scary, but they're usually not as bad as we fear. Just make sure whoever works on it knows their way around BMW electrical systems, and you should be good to go!

Thank you so much everyone for your help and advice! I wanted to update you all on what happened. I finally got the courage to take my BMW to a new mechanic, and I'm so glad I did! Turns out it was indeed just a faulty sensor connection, just like some of you mentioned. The mechanic found some corrosion on the wiring harness and fixed it right up, cleaned the connection and replaced a small section of wiring. The whole thing cost me about €120, which was way less than I was worried about spending. The car's running perfectly now, no more check engine light and that rough running is completely gone. Honestly, I feel a bit silly for being so nervous about it. The new mechanic was really thorough and explained everything clearly. It's such a relief to have this sorted out. I really appreciate everyone sharing their experiences, it helped me understand what I was dealing with and gave me the confidence to get it fixed before it turned into something bigger. Next time I won't wait so long to deal with these kinds of issues! Thanks again for all your help!