general problems of the 2012 Mazda CX9 - part 1

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.

On August 14, 2020, the brake booster along with the master cylinder failed, resulting in very dangerous and frightening driving conditions, and the parts were replaced with Mazda original parts. This was an ongoing issue with the Mazda cx-9’s. I reported it to the NHTSA, complaint number 11480067. On January 4, 2023, the brake master cylinder and booster failed again resulting again in very dangerous and frightening driving conditions. The car was driven only 25,383 miles before the brakes failed the second time. The Mazda parts were defective and continue to be so after many years with no effort by Mazda to improve these parts. Attached are the repair invoices for both incidents. I have tried contacting Mazda and they refuse to address the issue.

Brake power boost failure.

I was driving along the highway and traffic began to slow. I pushed the brakes and the car did not stop.

Brake booster internal failure - this is a known issue and a safety hazard on Mazda cx 9 models and should be investigated again regardless of the age of the vehicle.

Brake booster failure caused a near miss. Wife driving with 5 year old daughter in the vehicle. The stopping force required on the brake pedal became excessive and the stopping (safe braking) distance significantly increased causing emotional distress. My understanding is this part (brake booster) has a defective diaphragm that deteriorates over time. The extended warranty created for this particular issue did not cover the vehicle at the time of the failure.

The contact owns a 2012 Mazda cx-9. The contact stated while driving 25 mph and approaching a stop sign, while depressing on brake pedal, the vehicle failed to stop. The contact stated that there was no warning light illuminated. The contact stated that she pumped the brake pedal and shifted gears to neutral until the vehicle came to a stop. The contact was able to drive to her residence. The contact took the vehicle to an independent mechanic and was informed that the power brake booster and master cylinder needed to be replaced. The vehicle was repaired. A dealer was not contacted. The manufacturer was informed of the failure. The failure mileage was 29,805.

I was driving slowly about 30miph and began hearing a hissing noise when I depressed the brake pedal. Once I pulled into my driveway a small incline, and pushed the brake pedal it was very tight and stopped at a point, but would not go further, tried shifting different gears. Finally brake depressed. Hissing has continues, very stiff brake pedal.

Brake booster on vehicle went out while driving, hard to engage brake and slow vehicle to a stop.

The brakes suddenly became very difficult to press as if I did not have power brakes. No warning lights came on and it became very difficult to stop the car. Then if I had to break suddenly and hard it would stall. I brought it to the repair shop and the brake booster was defective. The brake booster along with the master cylinder had to be replaced. It was a very dangerous and frightening experience the brakes suddenly difficult to use. I contacted Mazda customer service and they did not care. I then tried to escalate the issue over the last two years but it was impossible to contact anyone and all emails came back undeliverable. I just recently learned that I can report this danger to the NHTSA.

When applying brake, hear hissing sound down at feet. Hard to stop, feels like pedal is pushing back. This happens at all speeds, even when putting car into gear from park. It has been ongoing for about 2 weeks. Mechanic advised it is the brake booster.

Purchased from a certified pre-owned Mazda dealer. . . . I experienced, with no warning, my brakes become hard to press. It happens in reverse, coming off cruise, slow/fast speed, etc. I have to use an extraordinary amount of effort to press the brakes and bring the car to a stop. If someone pulls out in front of me, there is no guarantee I would be able to operate the brakes quickly enough to avoid an accident. I have children I transport and it is concerning for me as a mom especially. A few times the pedal will �release� and operate normally after the extra pressure is applied which causes the car to jerk to a stop because the brakes were being pressed very hard. Most times, extra pressure is required the entire time. This is a major safety concern and an issue I am aware is common in this model. Mazda extended this warranty to 90k and 7 years back in 2015; however, this does not cover used car purchasers. The issue was not disclosed to me in my purchase date of 12/12/2016. Had I known this major component could fail, I would have made a more educated decision on whether to purchase or request the faulty system be corrected.

Brake pedal has become harder than usual to depress and the car does not start stopping until the brake pedal is depressed harder and further down. Also there is a hissing noise once the car stops and the brake pedal goes further to the floorboard. Once stopped and sitting the car will lurch as if it has been hit in the rear end. This all happens on any type of roadway. This has been going on for about two months and getting more pronounced.

I am now experiencing what Mazda mailed owners previously (see attached ssp93 owners notice) regarding "power brake unit warranty extension program ssp 93 2007-2013 Mazda cx-9". I strongly believe that this is a safety issue since I find myself running stop signs when I try to stop the vehicle at an intersection. I know that Mazda extended the warranty to 7 years on it's ssp93 bulletin. But what happens to owners like myself who do not fall within that time-frame and are now experiencing this safety issue? it is unconscionable, that since Mazda has acknowledged this problem, that the owner like myself gets stuck with this safety problem concerning failure of the braking system on the cx-9. Please advise. Thanks.

Power booster high pitch sound when pressing brakes and brakes are hard when pressed then go soft and hard to stop the car.

Brake pedal action feels spongy, soft. Requires extra force to stop the car when moving on city streets.

When pushing the brakes the pedal is �hard� as if the pedal was on the floor there's a hissing noise like air is leaking. If you need to make a sudden stop it does not happen the brakes are so hard the car won't stop!! this defect happened suddenly there was no gradual warning !.

Tl the contact owns a 2012 Mazda cx-9. While attempting to accelerate from a traffic light, the accelerator pedal was depressed; however, the vehicle failed to respond. The contact stated that there were no warning indicators before or after the failure. The brake pedal also became extremely difficult to depress. The vehicle was towed to continental Mazda (located at 2363 aurora Ave, naperville, IL 60540, (630) 352-5900) where it was diagnosed that coolant entered the engine oil and caused the engine to fail. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified and provided case number: 1-2189354066. The approximate failure mileage was 52,000.

2012 Mazda cx-9. Consumer writes in regards to brake power boost unit failure. The consumer stated that when pressing the break pedal there is a hissing and thunk noise. The engine would stall. The dealership and manufacturer were notified, but denied assistance.

I was on the interstate (driving 60+mph) and the car in front of me slammed on their brakes for an unknown reason. I tried to use my brakes but they were rock hard and the pedal wouldn't depress. I was forced to swerve to the right, still having no brakes, and barely made it over 3 lanes to the shoulder of the road. In doing so, I caused total chaos around me, caused a tractor trailer to start to jackknife, which caused a chain reaction behind him. It was a total miracle that no accidents were caused and no one was killed. I called my mechanic from the side of the road, hysterical. He looked in his database and found that Mazda had known issues with their power brake booster. I subsequently found a letter from Mazda instructing owners "if your vehicle is functioning properly, there is no need to contact your dealer. " are you kidding me???? my brakes were fine until they weren't, then I narrowly avoided being killed or causing the death of another because apparently Mazda's body count wasn't high enough to issue a recall.

Brakes slip causing unexpected increase in stopping distance even at low speed. Very concerned about family safety. Research found issue was noted previously and supposedly closed, but many complaints like mine have been filed since. How many deaths must NHTSA see reported until they take action and recall this admittedly faulty design?.

The break booster went out without warning and could not stop the vehicle.

I parked my Mazda after coming back from my lunch break and noticed that my brake pedal was a lot harder to push. I also heard a noise coming from what seemed like the pedal. It sounded like I was letting air out of a balloon. After work, while driving in reverse to back out of my parking stall, I noticed the brakes were still very hard to push. The noise was also still happening, but it was louder. I decided not to drive my vehicle until I had it looked at by a mechanic. When my mechanic started my vehicle and began to test drive it, the noise was gone, but he also felt that it was very hard to apply my brakes. The problem was diagnosed as a bad brake booster. After the problem was diagnosed, I researched common complaints with this, and discovered that it is also an issue in the earlier models (2010 and 2011) this is a major safety risk that I would like investigated. Thank you!.

I was driving to get lunch from work and went to stop at at traffic light on a very busy road and my vehicle wouldn't stop. The pedal was hard and I had to push it all the way down and narrowly missed the vehicle in front of me. I drove carefully back to work and had the vehicle towed to the shop. It was the brake booster. I then did some research on the subject since my vehicle is still fairly new and it seemed odd. I saw so many complaints and it scared me. This needs to be recalled before someone gets seriously hurt!!.

Letter from senator gardner on behalf of constituent regarding his concerns about a defective brake design system which exists in the Mazda cx-9.

Virtually complete loss of braking. Quick onset. Apparently the same underlying defect as investigated in 2008-2011 (incorrectly closed) and in TSB #ssp93 NHTSA id #10117767. The dealer had the car in for another issue (recall) in March; but did not fix this issue (not allowed to speak of it -- unless the customer brings it up (personal communication 7/3/2018). Nhtsa staff should have noticed that the 2012 TSB is essentially a continuation of the core issue from 2008 onward. A failing booster should increase the effort to brake, it should not be permitted to result in complete loss of functionality!.

Apply with the brake peddle is pressed. Can will continue roll, and in some cases, become very hard to stop. So far, not hit anything, but have had issues on not being able to stop at stop lines even at slow speeds.

The braking system did not function correctly resulting in a crash. Brakes were hard and could not be depressed when a vehicle stopped quickly in front of me. Took the car to Mazda dealership and they informed me that this is a known problem and replaced the brake booster under a "special warranty". This needs to be a safety recall, I was never notified of this safety issue. It is imperative that nhtsb reopen the investigation on this problem as it does not only involve 2010 and 2011 cars and does not only occur in "high ambient temperatures". Vehicle was in motion and was slowing on an slight uphill grade. Vehicle is 5 years old and has 53,000 miles.

I was going 10mph to stop in front of my daughter's school to pick her up when my brakes were difficult to apply. I had to use both of my feet to stop my car from crashing into the car in front of me. I heard a hissing sound when I applied my brake. The lights on my dash abs lit up and then my car shut off. I was scared and didn't know what happened. I waited a few minutes when no one was in front of me and tried to drive away and it happened again. I left my car at a gas station for a tow truck to get it. I waited for the car to be towed and googled what happened. Turns out over 50 other people have had the same issue happen with the same car and year. The brake booster assembly went out between 43000-50000 miles. Some scenarios were worse than mine. They were driving faster than 10 mph and could not stop the car in time or at all. There is no recall and the dealership said because I moved to guam from washington I had to pay out of pocket for the repair. I had it replaced and in December and still have not been able to drive it. The part they replaced is faulty too. And they ordered a new part. So its sitting till the part arrives on the island of guam. This site I was on has lots of people with similar issues with the brakes. Please look into this. The brakes are a big issue in a car. . Read more...

Brakes do not stop vehicle immediately, it is hard to apply brakes.

Brake booster, hissing noise and hard brake. No warning, brakes don't stop well. Brake booster continues losing vacuum pressure as long as the brake is applied. I have noticed online multiple complaints and a known problem.

Hissing sound when braking in motion or parked. When driving up to an intersection after exiting the freeway about 20 mph car would not stop no matter how hard I stepped on the peddle. Luckily I was able to slow before hitting the car in front of me. When stopped at a light car lunged forward while my foot was on the brake. This happened again while I was waiting for my daughter at school. It lunged up and nearly hit the car in front of me! scariest thing in the world to not be able to brake!!.

When stepping on the brake peddle a hissing sound is heard and the brakes no longer stop the car.

The car breaks became hard to push started hissing and wouldn't respond to break till the pedal was almost pushed to the floor. There was no warning. We were on the highway.

My brake becomes really stiff when pushed. This specially when coming to a stop where you have to use all your energy to make the car stop. My wife use this car with 2 young kid 5 and 1 and one on the way. This really worries me specially that its happening to a lot. It may not seem a lot to Mazda but its a lot for the consumers specially when lives are at risk. Pls fix this problem before its too late . I was even thinking of trading to the new 2017 Mazda but now I have doubts.