Problems · by component
2011 Mazda CX-9 service brakes problems
97 owner complaints to NHTSA about the 2011 Mazda CX-9 cite service brakes, 57% of all 171 complaints for this model year.
Complaints
97
57% of all complaints
Crashes
4
Reported by owners
Fires
0
Reported by owners
Injuries
0
Reported by owners
What owners say about the service brakes
Verbatim from NHTSA complaints, newest first
“Brake booster failure. The power assisted braking has stopped working. There are no leaking vacuum hoses and the check valve is working. The brake pedal travels to the floorboard.”
“The contact owns a 2011 Mazda CX-9. The contact stated while driving 20 MPH, there was an abnormal sound coming from the brakes. The contact stated that the brake pedal was firm and difficult to depress while attempting to stop the vehicle. The vehicle was not diagnosed or repaired. The manufacturer was contacted, and a case was filed. The failure mileage was 67,000.”
“Braking trouble recent in weeks in 2011 Mazda CX-9 vehicle. Had mechanic (Euro Motorsports in Chagrin Falls OH) check it out. Turned out to be a faulty Brake Booster. Mechanic test drove car; braking failed and he almost rear-ended another vehicle. He found on line a Mazda service notice dating from April 4, 2014 called SSP93. Mazda issued an extended warranty of 7 years or 90,000 miles, whichever came first, to have defective part replaced by an improved part. But we were never informed by Mazda of Bedford, where we bought the vehicle. Currently, our vehicle has about 83,000 miles. Never knew there was a problem until recent trouble with the braking. There are thousands of CX-5, Cx-7, and Cx-9 vehicles in operation in U.S. right now; probably many owners have no idea there is a brake defect in their vehicles that could cause a serious accident, potentially fatal. Mazda should have done a recall in 2014, not an extended warranty. Although Brake Boosters are supposedly good for at least 150,000 miles of driving, our brake failure at around 83,000 miles proves otherwise. NHTSA should order Mazda to recall all vehicles with the defective brake part and replace…”
“SIRT: I PURCHASED MY 2011 MAZDA CX 9 FROM MY CLOSE FRIEND [XXX] ON DEC.05 OF 2014! [XXX] HAD NOT BEEN ISSUED A SPECIAL SERVICES PROGRAM ABOUT THE BRAKE BOOSTER! WELL I NEVER RECEIVED THIS INFO EITHER? IN FACT I HAD TWO RECALL THAT WERE TAKEN CARE OF BY THE LOCAL MAZDA DEALER HERE IN THOUSAND OAKS CALIF. THIS KNOWN BRAKE BOOSTER DETONATION HAS BEEN KNOWN BY MAZDA.IOT IS A VERY DANGEROUS CONDITION AND IS NOT TO SAFE TO DRIVE THE CAR AT ALL- I WILL NOT DRIVE THE CAR AND SEETHE ORIGINAL MATTER SHOULD HAVE BEEN LET IT BE KNOWN TO MYSELF AND FEEL THE MATTER SHOULD BE ADDRESSED ASAP BY MAZDA -THANK YOU [XXX] ADDING BACKING -VERY HARD BRAKE - WHEN DRIVING IT HAD TO REALLY STAND HARD ON THE BRAKE TO STOP CAR B! ALL INDICATIONS POINT TO A BRAKE BOOSTER FAILURE ! TO SUMMARIZE IO WAS NEVER NOTIFIED BY MAZDA ABOUT THE SPECIAL SERVICE PROGRAM FOR THE REPAIR OF THIS EXTREMELY UNSAFE BRAKE PROBLEM!”
“THE BRAKE PEDAL SEEMS HARD TOO STOP THE CAR WHEN IN MOTION ON PUBLIC STREETS, VEHICLE CONTINUES TOO ROLL UPON PUMPING BRAKES, HAVE TOO CONTINUOUSLY PUMP THE BRAKE HARD TOO STOP THE VEHICLE, HAD THE FRONT BRAKES REPLACED RECENTLY, AND BRAKE PEDAL IS STILL NOT FUNCTIONING CORRECTLY, POSSIBLY THE BRAKE BOOSTER.”
“I WENT FROM HAVING BRAKES TO HAVING TO PUSH THE BRAKE TO THE FLOOR, WHICH STILL DID NOT STOP THE CAR, ALL IN THE SAME DAY. I WAS LUCKY NOT TO WRECK BUT COULD NOT STOP FOR STOP SIGNS OR STOP LIGHTS ALL WHILE MY 22 MONTH OLD WAS IN THE VEHICLE. SOMETHING IN THE BRAKE SYSTEM MESSED UP, AND IT STILL HAD A FULL THING OF BRAKE FLUID. I BELIEVE THAT IT IS THE BRAKE BOOSTER CAUSING THIS PROBLEM. *TR”
Showing 6 of 97 reports. Read every report on NHTSA.gov.
Data from NHTSA Complaints API (owner reports, unverified) · synced Oct 28, 2026NHTSA vehicle page
Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.