Unlike many people who despise "idiot headlights", I appreciate BMW's proactive approach to overseeing important aspects of their car's maintenance. In this case, I knew I needed new brake pads before the sensor detected it. In typical human laziness, I waited until the last minute to get the job done, and the sensor eventually caught up with what I knew. Next time I'll change the gasket before the sensor tells me so I don't have to replace the sensor. It's not difficult to replace, but it's very dirty. The part works great and the light was easy to reset without additional tools.