ABS activating during normal stops.

Ever since i put on 285's (i think its a coincidence) my abs has been activating during normal stops. It doesn't always turn on, but it very frequent. It only activates from about 20-10 mph and for one or two seconds then turns off before i come to a complete stop. No abs light.

I've checked all the connections and wires underneath the truck, but nothing seemed to be noticeably corroded or damaged.

Any Idea's would be appreciated, as this is getting really annoying.

 

Code pulled: 33 right rear speed sensor malfunction. I cleaned up the connections and made sure there wasn't any damage to the tip of the speed sensor. The light turns on immediately upon moving after the light it reset with the same code. I just ran to the store and the light was on on the way there, but it was off on the way back.

Think the speed sensor is going bad?

Wasn't getting a light before but there was a code in there.

 

Okay, so I swapped the wheel speed sensors on the passenger side of the truck, and the code did not move. Looks like i should be looking for a wiring problem now?

 

Found a broken wire. Problem solved!

 

Since you said it started with the new tires, have you checked all your tire pressures and that all are indeed the same size and load rating? A speed mismatch due to uneven inflation or even a different tire (yes, it has happened) can cause what you describe and cause a sensor code as well. Some ABS systems give a different code for sensor speed mismatch, while others simply log the same code as if that sensor circuit was open or had no AC signal voltage. I'm not sure which way the these trucks are, but worth a quick check. Otherwise, check the sensor resistance with a DVOM, and measure AC voltage from the sensor while spinning the wheel by hand.

 

Good news.