My 2001 4x4 F150 ABS comes on under a few MPH all of the time, I can feel it in the brake pedal. Some times it comes on when I' going a few MPH without my foot on the pedal, I can feel a buzz in the floor. My mechanic has cleaned all the sensors & checked everything. I replaced the rear diff speed sensor since its cheap and I’ve seen posts that it fails a lot. Didn’t fix it
I measured the front wheel speed sensors, both are about 450 ohms. Is this correct?
I flushed/bleed the brake fluid, 2 quarts. Didn’t help.
I’ve read that the Kelsey-Hayes 4WABS EHCU module fails, but when it goes the ABS pump is on all the time. Mine is on at slow speed all the time.

What should I try next?

Jerry

 

Does Your Speedo Act Erratic? Any Noise From The Rear End?

 

Speedometer isn't erratic. No noise from rear end.

 

Maybe a front tone ring with a broken tooth? It's not uncommon and easy to miss.