I was parked idling in my truck today 2001 f150 screw 4x4 and the and light came on. I have not hit the brakes hard or anything and there appears to be no leaks. My brakes seem to be working as always. Can anyone tell me why my light has came on. I have 311834 miles and it has never came on. No recent brake work or anything done.

 

It's probably just a failed sensor. They don't last forever. However, it needs a computer diagnosis to determine what the problem really is unless a visual inspection reveals something obviously wrong.