anti-lock brake warning light

[Tom7227]

2002 F150 with 170K on it. The Anti-lock brake warning light came on this weekend. Doesn't seem to be anything wrong but then I guess you won't find out about that until it's too late. Any ideas? Tempted to unplug the battery and let it reset and see if that solves it.

Thanks for the help.

Tom

[Macgyver55]

My first guess would be the rear differential sensor is bad. If you have a humming sound while driving one of the fronts may have a bad hub and bearing assembly. Have the code pulled and you will know for sure....

[Jeremy airjer W]

The light typically goes out if the problem is no longer present. If it comes on and stays on than there is a problem with the self check and as mentioned the most likely is a speed sensor and even more likely the one in the rear diff. The self check in a nutshell makes sure everything it needs is present. If it sees something "out of range" it shuts down the system and keeps the light on. An open sensor is a good example. If the light comes on, goes out, and then comes on after you start moving than a loose wheel bearing or a broken exciter ring would be more likely. It a bad sensor can still pass the self check and just not generate a good signal.

The code or codes will shed a lot of light on which direction to head.

[low277]

I have a Chevy pickup that the light came on, then went out. happened a couple of times. then I noticed noise from the front wheel area. I had a wheel bearing that was getting bad.

[ozzie]

i get the abs light and the brake light at the same time but if I turn off the vehicle and restart the lights turn off. checked for play in the bearings and all seemed good so we r letting it go until it creates a problem

[JOHNBIGDOG]

Those two lights usually come on together when the brake fluid is low. Give it a look.

[Tom7227]

The problem was a right front wheel speed sensor. $275 in part due to corrosion.