I have a 2002 Explorer that had a whining rear, changed it out with a good rear out of my parts truck and now I have an ABS light on. It says something about input to the sensor and output from the sensor and left and right wheels. 4 Codes in all. I changed the speed sensor in the top of the rear to the one that was in this truck because the light wasn't on before and it still has this light. Any ideas? Thanks, John

 

when you turn the key on and start the truck, the abs light comes on for a few seconds, the then runs a continuity test to the front two ABS and the one rear ABS sensors. If all are connected and have continuity, the light goes out.... After you put the truck in gear and start moving, maybe 5 MPH, the computer runs a comparison test to see that all sensors read about the same speed. If one is bad, the light comes back on.... I once changed a front hub and when pushing the plastic plug connector back together i got it cocked and smashed on of the two prongs inside the plug. You might check that on the rear.