Tokyo , Japan ( CNN ) -- Toyota has added the brake systems of the latest Lexus hybrid vehicles to a growing list of problems with various models , the company said Friday . The company said it was checking the brakes on the Lexus vehicle model HS250h -- as well as a Japanese model called the Sai -- because they use the same system as that used on the 2010 Toyota Prius . Toyota has announced no recall of these vehicles , however , and said it has not received any complaints about the brakes from consumers . But the U.S. National Highway Traffic Safety Administration announced Thursday it is opening a formal investigation into problems with the Prius , Toyota 's fourth-best selling model in the United States and the best-selling model in Japan . The company has acknowledged a software glitch that is causing problems with its braking . It said it is looking further at the best way to repair the problem . On Thursday , Ford announced that it was changing the software in the braking system for its Fusion and Mercury Milan hybrids to correct an occasion glitch in the old software . Ford said no injuries had been reported involving the problem . The Fusion/Milan 's issue seemed less serious than that of the Prius , said David Champion , the head of auto testing at Consumer Reports . The NHTSA investigation involves only 2010 model year Prius hybrids , which went on sale in the middle of last year . There are only 37,000 of those vehicles on the road , according to the agency . The Prius , which is built in Japan , is not one of the eight models affected by two recent recalls -- covering several million vehicles -- to fix problems with sticking gas pedals . All of those models were built at North American plants . NHTSA said its Office of Defects investigation has received 124 reports from consumers about problems with the Prius brakes , including four reports that involved crashes and two that resulted in injuries . No fatalities have been reported . Investigators have spoken with consumers and conducted preliminary field work . Late Wednesday , Toyota President Akio Toyoda spoke with U.S. Transportation Secretary Ray LaHood , reassuring him that Toyota takes U.S. safety concerns seriously and puts safety at the top of the company 's priorities , according to NHTSA 's statement . Toyota had only limited comment on the probe . `` We have heard about NHTSA 's intention to begin an investigation . Toyota will cooperate fully with NHTSA 's investigation , '' the company said in a statement . Even if the solution ends up being a relatively simple and inexpensive software adjustment , the Prius braking problems come at a bad time for Toyota , which has seen its prized reputation for quality and safety badly damaged by the recalls and the news attention given to them . The company has estimated that the problem with the gas pedals will cost it about 100,000 sales this year and $ 2 billion in repair costs and lost revenue . Other experts say the problem could be more long-lasting if consumers who once trusted the Toyota brand decide to shop elsewhere . The Prius problem is a `` disconnect '' in the vehicle 's complex anti-lock brake system that causes less than a one-second lag before the brakes start to work , Toyota said Thursday . At 60 mph , though , a vehicle will have traveled nearly another 90 feet before the brakes begin to take hold . The company also said it changed the braking system software in January for vehicles built since then . But it has yet to determine how to fix the brakes of vehicles already on the road . CNN 's Kyung Lah and CNNMoney.com 's Peter Valdes-Dapena and Chris Isidore contributed to this report .
Toyota has admitted to a software glitch that is causing problems with braking . Toyota : Prius `` disconnect '' in anti-lock brake system causes less than a second lag . Prius is not one of the eight models affected by two recent recalls . Toyota estimates the problem with gas pedals will cost it $ 2 billion , 100,000 sales .