In another serious blow to Toyota, the National Highway Traffic Safety Administration said Thursday morning that is opening a formal defect investigation of the 2010 Toyota Prius, examining allegations that the hybrid vehicle momentarily loses braking when it goes over uneven roads or hits potholes.
The investigation, launched after the agency had received 124 reports from consumers, is another blow to Toyota's eroding reputation for quality and safety. It comes after the company was forced late last month to suspend sales and production of its most popular vehicles because of defects that could cause sudden acceleration.
The Prius uses an advanced braking system that has both conventional brake pads and a regenerative system that helps charge the battery from the energy given up when stopping the car. A computer determines which brake mode to use at any given moment.
NHTSA officials did not say what they think may cause the loss of braking, but Transportation Secretary Ray LaHood said that safety investigators have received reports of four crashes.
"Safety is our top priority," LaHood said. "That is why in recent weeks NHTSA has also issued a consumer advisory on the recall of several models of Toyota vehicles and the Pontiac Vibe involving pedal entrapment and sticky accelerator pedals. We will continue to monitor these issues closely."
Toyota is currently conducting two recalls to correct problems that can cause sudden unintended acceleration across much of its product line. The company last fall said accelerator pedals could become jammed by floor mats, and last month it said its gas pedals were sticking in some of its most popular models.