Which parts fail
Components named in complaints (service brakes, ABS, rotors and pads, parking brake).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2011 Mazda CX-9 owners, lightly cleaned up (personal details are redacted by NHTSA).
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. …
Tl* the contact owns a 2011 Mazda cx9. The contact stated that while his wife was driving approximately 13 MPH and attempting to slow down, the brake pedal was harder than usual to depress. As a result, the driver rear ended the vehicle in front causing a five vehicle collision at a traffic light. None of the frontal air bags deployed. The police were present and a police report was filed. There were no injuries reported. The vehicle was towed to an impound lot where the insurance company was scheduled to have an inspector inspect the vehicle. The vehicle was not taken to the dealer for a diagnostic. The vehicle was not repaired. The manufacturer was not notified of the failure. The contact referenced NHTSA action number: pe14005 (service brakes, hydraulic). The VIN was not available. The approximate failure mileage was 86,000.
The brakes did not respond to typical pressure required to stop... When I pushed harder on the brake pedal it felt like the brakes were starting to engage, however I could not get them to fully engage and stop in time to avoid rear ending the vehicle in front of me. I took evasive action and jumped the curb and directed the vehicle at bank of newspaper stands in order to come to a complete stop.
I had 3 children in car seats, myself and my oldest son in our cx9. I crested a hill and started down the other side and I applied the brakes to slow down and they were hard and would not allow me to stop. I almost hit the truck in front of me. He was thankfully watching his mirror and ran a red light to get out of the way so I didn't hit him. After standing on the brakes for what seemed like a life time they finally engaged in the middle of the intersection and hissed with a loud squealing noise. I removed myself from the intersection and at 5 miles per hour went to the nearest mechanic. I was told to call Mazda because the power assist braking system had failed. I called Mazda and they told me not drive it as it was unsafe. They would have it towed to the nearest dealership and would take care of it. The nearest dealership is dolan Mazda Kia in reno nevada. …
My brakes did not respond as they normally would upon application of the brake pedal when approaching an intersection on Thursday morning. It felt almost like there was a pillow under the brake pedal. This occurred once on Thursday morning, and once on Friday afternoon. Friday evening brake fluid was filled to ensure that there was not a lack of fluid causing the problem, however the problem again occurred several times on Friday evening after adding brake fluid. By Saturday morning it was worsening both in frequency (occurring with every application of the brake) and severity (felt as though no matter how long and hard I applied pressure to the brakes it would not perform in a manner that would be effective in anything other than very slow speeds with excessive space between all vehicles). …
This is the second happened to my Mazda cx9, 2011. The brake started to have hissing sounds while stepping on brake. The brake pedal is harder than usual to depress. The brake functions has been reduced around 30~50% less than normal. This has put deriving safety in jeopardized. This is the second time my cx9's brake booster failure. The first time is in year 2012. I worked with Mazda to have brake booster replaced. However, dealer seemed not realized there is a warranty extended program from Mazda --- Mazda special service program -93 (ssp93). This is official recorded in NHTSA action number pe14005. Dealer tried contacting Mazda for this program. But Mazda kept not responding, it has been two weeks but still not message back from them. I paid the repairmen of the defective brake booster (parts & labor) from my own packet at this point. …
Approaching a red light on a dry sunny day, my brakes failed halfway through coming to a stop. At first my vehicle (2011 Mazda CX-9 sport with 56,000 miles) was slowing down normally and then suddenly there was grinding/crunching noises and despite pressing the brake, the vehicle was no longer stopping. I slammed the brakes, pumped a few times, and the vehicle simply failed to slow down or stop causing me to slam into the rear of the vehicle in front of me. I took the car into a mechanic who notified me that both of my "front calipers were possibly defective," and my front rotors were "uneven and wearing on the outside." however, my brake pads were good and did not need to be replaced. Good thing I was already stopping for the red light; therefore I estimate going about 10-15 MPH (speed limit on street was 35 and I was already midway through coming to a stop at the light). …
Sirt: I purchased my 2011 Mazda CX 9 from my close friend [redacted] on dec.05 of 2014! [redacted] 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 [redacted] 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 ! …
I noticed a significant problem braking on my cx9 to where I had to almost stand on the brake pedal to stop. Added brake fluid hoping that would help but did not. Took it to Mazda dealership in buford,ga and they confirmed the brake booster was causing the problem and strongly recommended replacement asap. They explained the problem is a known issue and Mazda extended the warranty to 90K miles. The problem for me was my '11 cx9 had 107K. I had no choice but to pay to have the problem fixed due to my personal safety. A couple days later I called Mazda customer experience and voiced my disappointment that this part was never recalled and people are driving around in unsafe cx9's. They did confess that if I would have called them 'before' my repair they could have reviewed the issue and perhaps offset some of the cost. …
NHTSA investigations
Brake Booster Failure
In March 2014, Mazda Motor Corporation (Mazda) initiated Special Service Program SSP93 to extend the warranty coverage for a specific brake booster fault condition on model year (MY) 2007-2013 Mazda CX-9 vehicles.According to Mazda's dealer communication for SSP93, the subject vehicles may exhibit a condition were the brake pedal is harder than usual to depress.
Brake complaints in other CX-9 years
Frequently asked questions
How common are brake problems on the 2011 Mazda CX-9?
NHTSA has 99 complaints about the brakes of the 2011 Mazda CX-9, 58% of the model year's 170 complaints. The component named most often is power assist › vacuum (1 mentions).
Is there a recall for 2011 Mazda CX-9 brake problems?
No. NHTSA lists no brakes recall for the 2011 Mazda CX-9, though it has 4 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2011 Mazda CX-9 brake problems start?
Half of the complaints with a recorded mileage happened before about 72,000 miles, and 5% before 25,000 miles.
Is it dangerous?
Owners linked 4 crashes, 0 fires and 0 injuries to brakes problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.