The National Highway Traffic Safety Administration said Friday it is opening an investigation into braking problems in 62,000 2010-11 Mazda CX-9 SUVs.
This is the second time since 2011 the government has investigated brake problems in CX-9 SUVs.
NHTSA said it has seven complaints of unexpected loss of power assisted braking in 2010-11 Mazda CX-9 vehicles. Complaints report incidents of the brake pedal suddenly feeling hard, requiring increased effort to stop the vehicle.
In 2011, NHTSA investigated brake master cylinder leakage in the 2008 Mazda CX-9. The Japanese automaker identified a manufacturing process issue with the master cylinder primary plunger surface finish, which may result in leakage from the master cylinder into the brake booster.
NHTSA said the leaks were generally detected by illumination of the brake malfunction indicator lamp and the government identified only nine reports alleging any effect related to brake pedal feel or brake effectiveness. The investigation was closed in April 2012, based on the “extremely slow leak rate associated with the master cylinder condition, the declining failure trend and the low probability that the condition could affect brake performance,” NHTSA said.
NHTSA said the new complaints allege symptoms indicating possible loss of power assist to the brakes, including hard pedal, increased effort and reduced brake effectiveness.
“Several allege hearing a hissing noise during brake application,” NHTSA said.
One said it was like the sound of the air leaving the tires. Many owners said the fix cost was $700 or more. No injuries or crashes have been reported, but some owners said they stayed off highways because they feared they couldn’t stop in time until they got the vehicle repaired.
Mazda spokewoman Tamara Mlynarczyk said the company was cooperating with NHTSA: "As always, we are fully cooperating with NHTSA on their investigation. We cannot comment further at this time."