Hi! I have an 05 explorer with advance trac (which the sensor is bad for) and my abs light came on and my 4x4 light flashes. I read alot about the tone rings and the speed sensors could be bad, but would they cause the truck to engage 4x4 when going slow and the 4x4 seems to be sticking/grinding. Something doesn't seem right and I'm not sure if its this sensor issue or if my transfer case is bad... Please help! We also just replaced a hub/bearing on the drivers front about 2 months ago.

 

The abs and 4x4 dont have anything to do with each other. I would worry about the transfer case engaging first. I would start at the accuator motor on the ts first clean electric connections and see if you can get it or stay disengaged if you cant take off the accuator motor and do it manually so it doesn't do any more damage to the ts. Remember dielectric grease on all electirc connections. If that's not the problem it may be the switch doubtful but anythings possible. Accuator motor may be bad.
Abs is probably the a wheel speed sensor there is one on the rear dif that maybe dirty you can take it out and clean it sometimes that works. The ones in front I don't know if you can get just the sensor or you have to get the whole ***.

 

If the 05 is like the older ones, there are some teeth on the inboard side of the front wheel hub that the ABS sensor "reads." If the teeth are dirty the ABS light will come on. You have to take the hub off to clean the teeth. I cleaned mine, and the ABS light stopped coming on.

 

Our part store is honoring the warranty on the new hub assembly that we put in last month so we are gonna pick that up in the am and try putting it on. Hopefully that solves the problem, We read the codes, and there was 6 of them, a few had to do with the battery and some said malfunction on RF speed sensor, this hub comes with a new sensor and tone ring. I am just hoping that helps the truck to stop putting the 4x4 auto on.