NHTSA Preliminary Evaluation PE08072

ODI HAS RECEIVED 64 CONSUMER REPORTS AND TOYOTA HAS RECEIVED 96 REPORTS THAT ALLEGE INCIDENTS OF INAPPROPRIATE ACTIVATION OF EITHER THE ELECTRONIC STABILITY CONTROL SYSTEM [TOYOTA NOMENCLATURE: VEHICLE STABILITY CONTROL (VSC)] AND/OR THE TRACTION CONTROL SYSTEM IN MODEL YEAR (MY) 2003 TOYOTA SEQUOIA VEHICLES.DURING THE ACTIVATION OF EITHER SYSTEM THE DRIVER LOSES THROTTLE CONTROL AND ONE OR MORE BRAKES MAY APPLY CAUSING THE VEHICLE TO SLOW SUDDENLY.DURING THESE ACTIVATION EVENTS THE BRAKE LIGHTS ARE NOT ILLUMINATED TO SIGNAL TO FOLLOWING TRAFFIC THAT THE VEHICLE IS SLOWING.SOME OF THE COMPLAINANTS ALLEGE ALMOST BEING STRUCK BY FOLLOWING OR CROSSING TRAFFIC BECAUSE OF THE UNEXPECTED DECELERATION.IN RESPONSE TO ODI'S INFORMATION REQUEST LETTER FOR PE08-072, TOYOTA INDICATED THAT IT HAS REVIEWED THE REPORTS SUBMITTED TO ODI AND TO TOYOTA AND THAT IT BELIEVES THAT THERE ARE SEVERAL ISSUES RESPONSIBLE FOR THE REPORTED INCIDENTS.IT IS TOYOTA'S OPINION THAT THE VSC SYSTEM WAS OPERATING AS DESIGNED AND THAT THE REPORTS ARE MOST LIKELY RELATED TO THE APPLICATION OF THE TRACTION CONTROL SYSTEM RATHER THAN THE VSC SYSTEM.AT THIS TIME TOYOTA HAS NOT DETERMINED THAT A SAFETY-RELATED DEFECT EXISTS IN THE MY 2003 SEQUOIA VEHICLES. THIS PRELIMINARY INVESTIGATION HAS BEEN UPGRADED TO AN ENGINEERING ANALYSIS (EA09-006) TO CONTINUE TO INVESTIGATE THE SCOPE, FREQUENCY, AND SAFETY-RELATED CONSEQUENCES OF THE ALLEGED DEFECT.