neleschmitz82
BMW 7 NOx Sensor Failure Causing Emissions Headache
Check engine light on
Exhaust leak
Fault stored
4 comment(s)
Thanks for sharing your experience! Good to know it wasn't too serious in your case. Do you remember roughly how much you ended up paying for the wiring harness replacement? Also, has everything been running smoothly since the repair, or have you had any other sensor-related issues pop up? Trying to get an idea of what I might be looking at cost-wise and whether this could be part of a bigger problem.
Hey again! Yeah, happy to update you! Got my car back from the shop last week and it was exactly what I suspected, just a faulty connection to the NOx sensor. Total bill came to 95 € which included fixing the cable connection and checking everything else was good. Pretty reasonable considering I was worried it might be something more serious! Everything's been running perfectly since then, no more check engine light and the emissions are all good now. The mechanic did a thorough job testing all the connections while they were at it, so I'm confident it won't be an issue again. Really glad I didn't jump straight to replacing the whole sensor, would've cost way more for no reason. Sometimes these BMWs just need a bit of TLC with their electrical connections. If your symptoms are like mine were, you might be looking at a similar simple fix. Just make sure they check the wiring and connections first before replacing any expensive parts. These sensor problems can seem scary but often turn out to be pretty straightforward fixes!
Thanks for such a detailed update! I actually just got back from my mechanic today. You were right, it wasn't as bad as I feared. Turned out to be a similar wiring issue, though mine cost a bit more at 150 because they had to replace a small section of the harness that had completely worn through. The mechanic was really upfront about everything and even showed me the damaged wiring before replacing it. They did a full diagnostic check while they were at it, which gave me good peace of mind. Car's running great now, passed emissions with flying colors and that annoying check engine light is finally off! Really appreciate you sharing your experience. It helped me avoid panicking about potentially needing a whole new sensor or catalytic converter. Goes to show how important it is to find a trustworthy mechanic who'll actually look for the real problem instead of just throwing expensive parts at it. Think I'll keep an eye on these connections during future services just to catch any issues early. Thanks again for the help!
Hey there! I had a similar issue with my 2016 BMW 5 Series last summer. The check engine light came on and I failed emissions too. After inspection, it turned out the NOx sensor wiring harness was corroded and had a loose connection near the catalyst. The mechanic showed me the damaged cables and confirmed the sensor itself was actually fine, it was just the wiring causing false readings. The fix involved replacing the wiring harness and checking all connection points. It wasn't a super serious repair, but leaving it unfixed would've eventually damaged the catalyst. From what you're describing, it sounds pretty similar to my situation. The failed regeneration could definitely be linked to faulty sensor readings. Make sure they properly diagnose whether it's the sensor itself or just the wiring before replacing parts. Hope this helps!