BMW X6 Water Sensor Triggers Rough Engine Performance

I had a similar issue with my 2015 BMW X4 last year. The check engine light combined with rough running turned out to be more than just a water sensor problem. When I took it in, they found that the connector plug for the temperature sensor was corroded and had a loose connection. The corrosion had spread to the wiring harness as well. The fix required replacing the entire wiring harness assembly and the sensor itself. It was actually pretty serious because if left unchecked, it could have led to engine management issues and potential engine damage due to incorrect temperature readings. The rough running was happening because the engine computer was getting faulty readings and adjusting the fuel mixture incorrectly as a fail-safe measure. Once fixed, the engine went back to running smoothly. I'd suggest not delaying this repair. Even though your previous mechanic experience wasn't great, this isn't something you want to leave unattended. Maybe try a certified BMW service center this time.

Thanks for sharing your experience! Really helpful info about the wiring harness. Would you mind letting me know what the total repair cost was? Also curious if you've had any related issues pop up since getting it fixed? I'm trying to figure out if I should brace myself for a big bill and potential follow-up problems.

Hey again! Since I got my X4 fixed up, it's been running like a dream, no more issues whatsoever! And honestly, compared to what I was bracing myself for, the repair was way less expensive than I thought it would be. The mechanic found it was just a faulty cable connection to the water sensor that needed sorting out. Total bill came to 95 € which was a massive relief considering I was worried about having to replace the entire wiring harness like I mentioned before. Turns out my initial concern about the corrosion spreading was a bit over-dramatic, the actual fix was much simpler. After they dealt with the sensor connection, the rough running completely stopped and the check engine light hasn't shown its face since. If your issue is anything like mine was, you might be looking at a similarly straightforward fix. Really glad I didn't put it off though, these things can definitely get worse if you leave them too long. Just remember, every repair case can be different, but hopefully yours will be as simple as mine turned out to be!

What a relief to hear about your experience! I bit the bullet and took my X6 to a different mechanic yesterday. You were right about not delaying, turns out I had almost the exact same issue. The mechanic found a loose connection and some minor corrosion around the water sensor. Thankfully, no major wiring harness problems! Total cost came to about 120 bucks for the diagnostic and repair work. The engine's running smooth again, and that annoying check engine light is finally gone. The new mechanic was actually pretty great, took the time to show me exactly what was wrong and fixed it right there. Funny how we work ourselves up thinking it's going to be some massive repair, right? Really appreciate you sharing your story, it gave me the push I needed to get it checked out before it could turn into something worse. Guess sometimes you just need to find the right mechanic!