The NHTSA have opened a preliminary evaluation (PE14-005) into certain 2010-2011 Mazda CX-9 vehicles. The NHTSA has already received seven reports from divers alleging symptoms of hard brake pedal feel, audible hissing noised during braking, and reduced brake system performance.

A similar investigation (PE11-026) was opened in 2011 for certain 2008 Mazda CX-9 vehicles. Mazda identified the problem as a manufacturing error in which the master cylinder primary plunger surface finish allowed leakage from the master cylinder into the brake booster. The investigation was closed April 9, 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.

If this preliminary investigation should lead to a recall, approximately 62,319 vehicles could be affected.