On multiple occurrences, driving at varying speeds, without traction control disengaged, the parking brake and traction controls warning lights and sounds activated for no apparent reason. the lcd dic indicated stabilitrak off and service brake system messages. tried engaging and disengaging both the parking brake and traction control with no change. when the parking brake was engaged however, the sounder began sounding again and when disengaged it would shut off. service brakes, rotors and calipers were replaced approximately 4000-4500 miles ago. first occurrence was about 1000 miles ago. has occurred 3 times total. possible bad abs sensor? *tr