436 of the 1,827 complaints filed about the Mazda CX-9 are about the braking system — 24% of everything owners reported. The worst model year for it is 2012.
436
Complaints
24%
Share of all complaints
25
Crashes
0
Fires
SERVICE BRAKES
The break booster went out without any warning or indicators while driving almost resulting in a collision. There are no warning lights on the dashboard.
NHTSA complaint #11746341 — an unverified report by a vehicle owner.
SERVICE BRAKES
My 2018 Mazda CX-9 experienced catastrophic engine damage after a radiator failure allowed coolant to enter the engine. The vehicle provided no dashboard warning, overheating alert, or coolant warning before the failure occurred. Modern vehicles are designed to alert drivers to overheating or cooling system failures. The lack of warning prevented me from addressing the issue and resulted in catastrophic engine damage. I believe this represents a potential safety defect in the vehicle’s cooling system monitoring and warning system.
NHTSA complaint #11723876 — an unverified report by a vehicle owner.
SERVICE BRAKES
If you press both the brake and gas at the same time (even if accidental), the onboard computer apparently thinks that the driver is confused, and it sets the gas flow to “idle”. The first time this happened was on the freeway, and I was very lucky to be able to coast into a gas station (thinking that I simply running out of gas - even though the gas gauge showed plenty of gas remaining). And so, I took it to Christian Brothers automotive the next day, and they ran extensive (and expensive) diagnostics. They found (to their surprise!) that this is the way the latest CX-9 works! The computer sees that you are on the gas and brakes, and so it “thinks” that you must be confused. And so, it sets the gas to “idle”. I believe this is an extremely dangerous action for the computer to take, and this behavior needs to be removed from all CX-9's IMMEDIATELY! And please don't just say (as others have) that the driver "shouldn't press both the brake and accelerator at the same". One might use the brake and accelerator at the same time for good reason, such as an icy road. But the computer SHOULD NOT DECIDE ON ITS' OWN TO SET THE THROTTLE TO IDLE!
NHTSA complaint #11699571 — an unverified report by a vehicle owner.
SERVICE BRAKES
my 2018 MAZDA CX-9 safety issue SCBS / SBS, LAS / LDWS, MASTER AND/OR HBC WARNING LIGHTS Forward sensing camera (FSC) stops functioning cause my car run rough even depress accelration and those light came on dashbaord -Forworad smart city brake support malfunction -smart brake system -front camera sensor malfunction
NHTSA complaint #11685844 — an unverified report by a vehicle owner.
SERVICE BRAKES
I am submitting this recall request because my vehicle has experienced repeated incidents of a serious safety issue. While driving—most often on the highway—a warning appears that says “Smart System Brake Malfunction.” Immediately after, the car begins braking on its own without driver input. This has happened multiple times and, based on online reports, it appears to be affecting many Mazda vehicles across different models and years. Each time, I have been forced to pull over, turn off the car, and restart it to temporarily resolve the issue. This is extremely dangerous, especially at highway speeds, as it creates a high risk of rear-end collisions and sudden loss of vehicle control. When reported to Mazda, the concern was dismissed as a “sensor issue,” but the repeated nature and widespread reports suggest a potential systemic defect that requires urgent investigation and recall.
NHTSA complaint #11682407 — an unverified report by a vehicle owner.
SERVICE BRAKES
I brought my vehicle in on 2/22/25 for a brake issue. I had to pump the brakes every time before I stopped to get the brake pedal to work. If I just hit the brakes the pedal would go almost to the floor. Greico Mazda has attempted 4 times to fix this issue with no success and has had my car in their shop for 4 months. I am now waiting for a Mazda rep to "fly in" to look at the car. They have replaced multiple parts on the car. I no longer feel safe driving this vehicle and have limited faith in Mazda to correct the problem.
NHTSA complaint #11665696 — an unverified report by a vehicle owner.
SERVICE BRAKES
Vehicle randomly displays "smart brake system malfunction," "forward smart city brake malfunction" and " front radar system malfunction." This has been going on for at least a year. I will be driving on a highway, trying to accelerate and these messages will pop up. I'm not able to accelerate when these messages pop up and I have to turn on my hazard lights and pull over to the side of the road. The only thing that clears these warnings are for me to completely shut down my car and restart it. Luckily I have been able to get over to the side of the road on the highway without an accident, but these warning lights pop up when it's sunny out and there is no reason for the car to act the way it does. I took my car to the dealer the first time it happened and paid several hundred dollars for them to tell me that they don't know why it happened. There are several forums posted online with people having the same issues. Online posts say to make sure the sensors are clean and that the malfunction can activate if it's too hot, rainy, snowing or foggy? In my experience, it has happened only when it has been sunny. When the system decides to malfunction, the car will not accelerate, and it could make it easier for the car to be hit by another car. It's like the car just shuts down.
NHTSA complaint #11662517 — an unverified report by a vehicle owner.
SERVICE BRAKES
I've had it repaired for over 30+ times. I'm tired of the car not being fixed. The last visit I was told maybe its the way I drive.
NHTSA complaint #11658142 — an unverified report by a vehicle owner.
SERVICE BRAKES
1. The navigation has a frosted crackle appearance framing the screen. It is difficult to read the navigation when needed. I know this has happened to other models of this vehicle and those were recalled and covered. 2. The brake senor keeps going off stating "SMART BRAKE SYSTEM MALFUNCTION". This goes off repeatedly while driving. 3. Then a second message pops up and reads "FRONT RADAR SENSOR SYSTEM MALFUNTION".
NHTSA complaint #11654693 — an unverified report by a vehicle owner.
SERVICE BRAKES
My wife has a cold. She picked it up during several uncomfortable hours in the emergency room. Our driveway is on a bit of a slope. She stopped the car, put it in park (she thought), turned off the engine, and got out. Something in the dashboard compartment had blocked the shift lever and the car was actually in reverse. It started rolling backwards down the driveway. She grabbed it and tugged with all her might and actually succeeded in stopping it when it got to the street. She managed to prevent our car from rolling into our neighbor's parallel parked car immediately across from our driveway. She also managed to hurt her arm quite badly. X-rays and CAT scans and exposure to every sniffling, coughing person in the ER later, and we learned she was lucky and did not break any bones, just sprained her elbow and shoulder. Very very lucky that she didn't get knocked under the wheel by the still open door of the car! My question is this: Can automakers create a safety device to prevent this? If the engine is off and the car is not in park, and no driver is detected in the driver's seat, can they automatically apply the brake? There could be a button or switch to undo the brake for towing. It seems the technology to do this has been around for decades, but the X-ray tech, the ER admissions nurse, my wife's orthopedist, even the lady at our insurance company all had stories of similar happenings. How can such a safety device become standard?
NHTSA complaint #11633972 — an unverified report by a vehicle owner.
SERVICE BRAKES
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.
NHTSA complaint #11620856 — an unverified report by a vehicle owner.
SERVICE BRAKES
Hello, I have been to a Mazda dealer complaining of clicking and squeaky brakes for 2 years now. Dealer replaced both front and back breaks and rotors around 22k year ago and to my surprise the issues persist, currently vehicle is at 49k. There is a TSB( 04-001/22) out for my vin and year, so they know its a manufacturing defect and all they do is throw white break grease and a month later the noise is there again when breaking , backing up. I am not the only one, people of reddit confirm this and so does a general google search. Besides that i love the car and the dealer was super cool about it all but I'm sorry, this is unacceptable, Every time i go get an oil change i ask about a fix and nothing.
NHTSA complaint #11619774 — an unverified report by a vehicle owner.
SERVICE BRAKES
Stiff brake pedal , more effort to stop and longer distant to stop.
NHTSA complaint #11614349 — an unverified report by a vehicle owner.
SERVICE BRAKES
My wife was taking my daughters for marching band and all of a sudden she tried to press the brakes but the brakes felt too hard and she was unable to stop the car safely. She had to take immediate action by moving the car to the shoulder to stop the car. There were no warning signs on the screen. The car was taken to the mechanic and the dealership. The dealership said that this was a brake booster issue which would be fixed for $1500. This is a serious issue which if had happened on the highway would have been tragic. Mazda and the dealership refuse to fix this free of cost since they say that they had already communicated about "an extension of warranty" to fix this problem in 2015 - at which time there were no issues with the brakes.
NHTSA complaint #11609995 — an unverified report by a vehicle owner.
SERVICE BRAKES
While driving the vehicle the brakes became hard to depress and a hissing came from my steering column, the car would not stop or respond to stop. I had to downshift to Neutral to get the speed slow enough to stop - and had passed through an intersection while in failure. I had also had symptoms I did not know at the time may be related which was at a stop at dunkins or a drive through at a stopped position - where the car would run rough the last few weeks. I thought the rough idle was gas related. I can no longer drive the vehicle and am told this is brake booster/pump issue / that other of the same parts in fords and other manufacturers are now extending customer sat programs like 13N02 because of faulty parts in the brake booster. the vehicle can be towed or seen for this problem. The vehicle has no existing coverage of the faulty brake booster. This is a car insured for my son [XXX][ to drive and It is a safety risk that this went while driving, i'm happy it was myself driving that day. Problem has been confirmed as a brake booster pump/booster failure by a service professional. No warning lights - just not able to stop the car when stepping on the brake. Thanks INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11593959 — an unverified report by a vehicle owner.
SERVICE BRAKES
Have been making repairs back to back since I bought it had to do four oil changes within that year then tires were completely worn electrical problems kept freezing spark plugs completely burnt discs were really rust car automatically turned off even though the battery is still good and still had gas had that happen twice and did more of a history search in it has had more complaints before every time try to take it to Mazda always be something with their system
NHTSA complaint #11589375 — an unverified report by a vehicle owner.
SERVICE BRAKES
The vehicle has tire pressure monitoring system malfunction warnings and parking brake malfunction warnings even after taking to dealership to be fixed. Was told it’s a known problem by Mazda, should be recalled, but there were not any current recalls for the issue.
NHTSA complaint #11559545 — an unverified report by a vehicle owner.
SERVICE BRAKES
Vehicle difficult to stop, believe it is a bad brake booster.
NHTSA complaint #11550478 — an unverified report by a vehicle owner.
SERVICE BRAKES
6/29/2023--Vehicle stopped suddenly with i-ACTIVESENSE system malfunction, Dynamic Stability Control malfunction, Engine malfunction, engine output reduced, Front radar sensor malfunction. Dealer said these faults due to bad battery--replaced battery per Service Manager [XXX] at Lakeland Mazda. 9/10/2023--Incident #2 with same faults as above with vehicle stopping suddenly at risk of creating a rear end collision. Lakeland Service Manager [XXX] now said that the faults are due to a faulty ERG valve. Lakeland Mazda and [XXX] are absolutely clueless as to the root cause of this problem and are releasing the vehicle back to the customer with the potential of causing a significant collision that can result in serious injury and/or death. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11548334 — an unverified report by a vehicle owner.
SERVICE BRAKES
I was driving normally when I started sowing down and noticed the brakes were harder to push. I finally stopped just before almost rear-ending a vehicle in front of me. It turns out the brake booster, a known problem that was not communicated to me a few years ago, failed and makes braking the vehicle harder, increases distance, and makes the vehicle unsafe to drive. The problem has been reproduced via a diagnostic test at Mazda of Gladstone dealership on 9/27/23. The dealership has been the only people who have inspected the issue. There were no warning signs, no warning lights, nothing. It was scary because I didn't think my vehicle was going to stop. It's completely dangerous. I have not gotten the vehicle repaired yet because I believe Mazda holds responsibility as this has been a known issue with their cars.
NHTSA complaint #11547325 — an unverified report by a vehicle owner.