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.

- Knoxville, TN, USA

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

- Sun City West, AZ, USA

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 !

- Waynesburg, PA, USA

So disappointed in NHTSA for not requiring Mazda to recall the brake booster failure! NHTSA's investigation into the brake booster failure was closed when Mazda agreed to an extended warranty for this manufacturing safety defect. Had the NHTSA pushed for a recall notice, we would have been alerted to this safety defect and could have had it repaired (it is known to fail around 62,000 miles). We contacted Mazda today about the warranty only to be told our vehicle warranty expired less than 3 months ago, resulting in Mazda's refusal to cover a known safety defect. Mazda's lack of commitment to resolving this safety issue is shocking. NHTSA's acceptance of Mazda extending its warranty for this known safety issue is disheartening as well. A manufacturing defect is a manufacturing defect; the problem should have been addressed when it failed or, at the very least, recalled and replaced. A time limit should not have been an option for a safety issue (or an out for Mazda). Perhaps it is time for NHTSA to reopen its investigation to protect the consumers against a known safety defect. Mazda certainly doesn't back it's product when it comes to safety issues!

- Rocklin, CA, USA

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.

- Montgomery, IL, USA

Applying brakes for 1-2 seconds resulted in no immediate stopping, only resistance from the pedal. After 1-2 seconds, the brakes were aggressivly applied. This resulted in "running a stop sign" and stopping the in middle of an intersection. This occurred on a city street multiple times before getting the car to a repair shop. On highways, braking had to begin well in advance to avoid possible crashes. We had to have the master cylinder and brake booster replaced. The vehicle has 55K mile on it.

- Carmel, IN, USA

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?

- Vallejo, CA, USA

I put my vehicle in the Mazda shop last year 2017 for a recall and I mentioned that there was something I felt in my brakes they told me that it may be dust and by driving it will go away, Mazda knew about this problem they should have taken care of it then.my vehicle was taken to ourisman Mazda dealership about 2 weeks ago and I was told that it was my brake booster & master cylinder labor is $709.47 and the parts are $537.98 and the brake flush is $202.61 total $1450.06 and my warranty expired in October 2018. I then called Mazda and I spoke to a Ms. Jennifer a customer experience representative and she said she would check into it.I then called back to ourisman Mazda and spoke to Mr. Emerson and he told me that he spoke to ms jennifer at Mazda and that my out the door price would be $553.16 and they have already ordered the part, they stated Mazda called off the recall and did a 7 year warranty or 90,000 miles my car is neither of them for a 2012, then they wanted to say its because when my car was purchased" then to tell me that when I put my car in last year for a recall if it was not making a problem they were not going to look for one" on these roads, my children, my grand children and the lives of all people I, and I'm sure a lot of people feel.I have been sick and without a loaner car and this is unexceptable I would greatly appreciate your help with this problem.my contact person with ourisman Mazda is Mr. Emerson 240-863-2429 and my contact info for Mazda customer rep is jennifer 800-222-5500 prompt 2 then ext 1133 (1-1930090754) the recall needs to be put back on, I was never notified that there was a extended warranty.this can result in serious injury or death, how dare them put a price on this.

- Silver Spring, MD, USA

Brakes were occasionally 'tight', had to be pushed very hard to get the vehicle to stop. When I pushed the brakes it sounded like air was being pushed out. Changed pads and brake fluid, flushed the air out. Only made it worse. Now the brakes are constantly 'tight' and after learning this is a common issue with this vehicle I'm going to replace the brake booster. Ridiculous that so many are having this issue and Mazda isn't recalling this part!

- Magnolia, TX, USA

Vacuum power brake booster failure, my brakes did not work and my car stalled. There is a warranty extension for this problem - not a recall - I never knew anything about it. A consumer must be notified of a recall but not a warranty extension but this is a very dangerous problem. I fear for the safety of others who may not know about the problem. If you don't know about it you do not ask to have it checked and when it fails you are in danger. I appreciate the warranty extension but I honestly think that I should have been notified. No one was injured and there was no property damage - I believe there should be some reconsideration regarding the decision not to issue a recall on this problem.

- Bridgeton, NJ, USA

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

- Silver Lake, IN, USA

The contact owns a 2012 Mazda Cx-9. while driving 35 mph, the brake pedal was depressed, but failed to engage. The vehicle was examined by an independent mechanic who diagnosed that the power brake booster needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 110,000.

- Louisville, KY, USA

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!

- Juneau, WI, USA

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

- Cherry Hills Village, CO, USA

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!

- Cherry Hills Village, CO, USA

At just over 90,000 miles I had transfer case problem that everyone is posting. As described by mechanic it is a manufacturing defect. Transfer case is placed just above catalytic converter (which throws off alot of heat) as a result oil in transfer case cooks over time and gears are destroyed. Mazda did not provide a way to replace and or check this fluid without taking down the entire transmission. Mechanic said I will have this problem again at roughly another 80-100,000 miles. Year and a half later I noticed a very soft brake. I replaced brake pads and drums, and brake fluid. I have a very hard brake which then sporatically goes soft. Again I looked up this issue and found again Mazda is aware of this issue and extented warranty to 90,000 miles. Again I'm just over the warranty allowance and now my brake power booster and possibly master cylinder need to be replaced. Both are known issues by Mazda. Unfortunately I was the lucky one who was the beneficiary of both problems just over the 90,000 mile warranty. I reached out to Mazda to request some assistance with at least the cost of the parts on the brake power booster. I was given a quick no by Mazda. Very frustrating since these are both known problems and they will not at least work with me on the parts cost.

- North Attleboro, MA, USA

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!!

- Canton, GA, USA

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.

- San Diego, CA, USA

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.

- Jeannette, PA, USA

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. Https://www.carcomplaints.com/Mazda/Cx-9/2012/brakes/service_brakes.shtml

- Hagatna, GU, USA