Electronic Stability Program and Traction Control System. It has a position sensor on the left UAC and right Upper A arm and a position sensor on steering wheel. Don't know when they started this maybe someone here will know. I think thy is why superlift had AEV come up with a module to hook in to the steering sensor and recalibrate for tire dia. Some with larger tires freaked out the brain as the newer models have gotten more sensitive.