Toyota Evaluates Unintended Acceleration Complaints in Remedied Vehicles
Brake Override Feature Operation Explained
TORRANCE, Calif., March 4 -- Toyota Motor Sales (TMS), U.S.A., Inc., has received verifiable information from the National Highway Traffic Safety Administration (NHTSA) about some vehicles whose owners have reported unintended acceleration after receiving the accelerator pedal recall remedies. As soon as Toyota received the vehicle owner information from NHTSA, it moved quickly to evaluate the vehicles and interview the owners.
Although most of these reports have yet to be verified, Toyota has been and remains committed to investigating all reported incidents of sudden acceleration in its vehicles quickly. Toyota wants to hear directly from its customers about any problems they are experiencing with their vehicles.
The results of the evaluations have been submitted to NHTSA for review. Though these reports involve a tiny fraction of the more than one million vehicles dealers have repaired to date, Toyota takes them extremely seriously.
As NHTSA is now reviewing the results of our evaluations, it is inappropriate for Toyota to provide specific information about the company's conclusions. However, the evaluations have found no evidence of a failure of the vehicle electronic throttle control system, the recent recall remedies or the brake override feature.
It is important to note that many complaints submitted to NHTSA either are unverifiable or lack the vehicle owner information required to facilitate follow-up. Nonetheless, Toyota is quickly investigating verifiable complaints of unintended acceleration and doing everything it can to ensure that our customers are confident in their vehicles and the remedies.
About the Brake Override Feature
The brake override feature is designed to be unobtrusive in normal driving conditions. It is designed to manage vehicle acceleration caused by interference with the accelerator pedal and is otherwise undetectable under normal driving conditions.
Using the accelerator pedal position sensors, brake light switch circuitry, and the vehicle speed sensors, this intuitive and intelligent extra measure of confidence helps ensure that vehicles can be controlled in the event that the accelerator pedal is trapped.
When the vehicle throttle is opened beyond the idle position, at speeds greater than five miles per hour and then the brakes are firmly applied for longer than one-half second, the override feature will reduce engine output to the idle position, allowing greater braking performance. If the brake pedal is then released and the engine speed does not return to normal operation, the vehicle should be brought to a stop with brake override, the engine shut off and the vehicle evaluated by a Toyota dealer.
The feature has sophisticated control logic intended to eliminate undesirable or inappropriate activation and is designed to be imperceptible. In certain driving conditions, unnecessary activation of brake override would create an inconvenient or even unsafe situation.
For example, the brake override feature does not operate if the brake pedal is depressed before the accelerator pedal. This logic allows for vehicles starting on a steep a hill to safely accelerate without rolling backwards, otherwise known as a hill start.
Toyota engineers have carefully calibrated the system control logic to prevent the system from interfering with efforts to free a vehicle by rocking it to gain traction in snow or mud. Since some drivers prefer to brake with the left foot, the system also recognizes this as an intentional action by the driver and will allow the accelerator to function normally.
Toyota is confident that the rigorously tested accelerator pedal remedies and the brake override feature are effective and firmly believes that, with these remedies, its vehicles are among the safest on the road today.