U.S. safety regulators have opened a probe into reduced brake effectiveness for an estimated 62,319 Mazda Motor Corp CX-9 large crossover vehicles from model years 2010 and 2011.
The U.S. National Highway Traffic Safety Administration said in documents filed online it has opened a preliminary evaluation into the vehicles after receiving seven consumer complaints of unexpected loss of power-assisted braking.
A preliminary evaluation is the first step in a process that could lead to a recall if regulators determine a manufacturer needs to address a safety problem.
A Mazda spokesman said the Japanese automaker was cooperating with NHTSA officials in the investigation.
Consumers said there were incidents of the brake pedal suddenly feeling hard, requiring increased effort to stop the vehicle, according to the NHTSA documents.
The NHTSA previously investigated brake master cylinder leaks in the 2008-model CX-9 but closed that probe in April 2012 because of a low probability the condition could affect brake performance, according to the NHTSA documents.
In the latest probe, however, the complaints said possible loss of power assist to the brake, reduced brake effectiveness, and several consumers reported hearing a hissing noise during brake application, according to the NHTSA documents.