I have a 96 Bronco with a 5.8 litre engine. The ABS light came on today and it is flashing a code 17. I checked the fuses and ground, swapped the main and ABS relays with the horn relay with no luck. Here is what happens, when I start the truck, the ABS light comes on for a few seconds, then goes off. If i have my foot on the brake, within 8-10 seconds after start up, I feel a pulse in the pedal, and the ABS light comes on and stays on until I turn the key off. The light comes on regardless of my foot on the pedal, but there is definitely a pulse or "thump", followed by the ABS light coming on. Any help on this would be greatly appreciated. i don't know what else to look for.