BMW Water Sensor Issue: Fix Before Major Engine Trouble?

Hey there! I had a similar issue with my 2016 BMW 1 Series last month. The check engine light came on, and the engine was running really rough, especially during acceleration. Turned out the wiring harness connecting to the coolant temperature sensor was corroded and had a loose connection. The fix wasn't too complicated, they cleaned the connector, replaced the damaged wiring section, and installed a new sensor since the old one was starting to fail. It wasn't a major repair, but leaving it unfixed could've led to bigger engine problems down the line. The symptoms match what you're describing. My advice would be to get it checked soon, as faulty readings from the water/coolant sensor can mess with the engine's timing and fuel mixture. That's what causes the rough running. Best of luck with the repair!

Thanks for sharing your experience! Glad you got it sorted. If you don't mind me asking, what was the final cost for your repair? Also, has everything been running smoothly since the fix? I'm trying to get a better idea of what I might be looking at cost-wise and whether this tends to be a one-and-done fix or if I should watch out for related issues popping up later.

Hey again! Great to give you an update, I got the issue fixed and my car's running like a dream now! The total bill came to 95 € for fixing the faulty cable connection to the water sensor. Pretty reasonable, considering how much smoother the car runs now. It's been about three weeks since the repair, and I haven't had a single problem. The engine's running super smooth, no more rough idle, and that annoying check engine light is finally off. The acceleration is back to normal too, no more hesitation when I press the gas. From my experience, once they fix the actual problem (in our case, the sensor connections), it tends to stay fixed. Just make sure they properly diagnose the root cause. In my case, it was just a corroded connection that needed cleaning and securing, but leaving it unfixed could've definitely led to bigger headaches down the road. Sound like what you're experiencing is exactly what I went through, so hopefully, you'll be looking at a similar straightforward fix. Let me know how it goes!

Thanks so much for all the details! I bit the bullet and took my car to a mechanic yesterday. You were spot on, it was indeed a sensor issue, but in my case, the sensor itself was completely shot and needed replacement. Total cost was a bit higher at 180€, but honestly, I'm just relieved it wasn't anything more serious. Got the car back today and what a difference! The engine's purring like it should, no more rough running, and that pesky check engine light is finally off. The mechanic was actually pretty decent too, took the time to explain everything and even showed me the old sensor. Really appreciate your input, it helped me make the decision to get it checked out sooner rather than later. Definitely feel like I dodged a bullet by not waiting too long. The car's running great now, and hopefully, it'll stay that way for a good while!