As I was driving down an onramp to a freeway, I depressed the brake pedal and the car did not respond normally. I had to push full force on the pedal to get the car to stop just before rear ending another vehicle. This occurred several times after without any warning light or anything. I took the car to the dealer and found out that the brake booster has stopped working. They are going to replace the brake booster and I have to pay for it. This car is no longer under factory warranty but has been well maintained by a Mazda dealer on a regular schedule.

- Lake Forest, CA, USA

I purchased a new Mazda cx 9 in the fall of 2010. After a few months, I noticed the traction control "tcs off" button illuminated while driving up a paved incline. After turning off the engine and restarting, the tcs-off button shut off. This happened a couple of times before my first servicing. I mentioned the issue to the Mazda dealership when I went in for regular servicing. They checked it and said they found no problem with it. Yet the problem continued sporadically. The tcs-off light occasionally illuminates on inclined roads, in rain or snow, when driving from a paved to an unpaved road (or vice versa). Still the dealership found no problems during servicing. Now in the third year of driving, I mentioned the tcs again to the dealership, and this time they said, oh yes, it is a problem.. Mazda released a bulletin about it, saying the tcs needs to be repaired for $340, and the car shouldn't be driven until it's repaired. Yet this is the condition I've always driven it in! and of course, now my warranty has expired, and I'm liable for repairs even though this problem existed right from the very beginning. The dealership has said they'd put in a call, and perhaps Mazda will cover at least part of the cost. If it had been repaired under warranty, I wouldn't be liable for the repair and I wouldn't have to pay for the rental car while I'm waiting. I'll see how it pans out. Very frustrating.

- Hastings On Hudson, NY, USA

I purchased this car from a dealer this year with $48,000 miles. It was in tip top shape. Recently the brakes are not working. It is not the brake pads, but a hissing sound in the line and no brakes. The cost to fix is around $1500 and I don't have a credit card or the money to fix at this time. In researching I am not alone with this problem. There are going to be some bad wrecks and problems if this is not addressed asap. I pray everytime I have to go out and stop really far behind pumping and trying to make them work.

- Columbia, SC, USA

The contact owns a 2010 Mazda Cx-9. the contact stated that the brakes would sporadically fail. The contact had to continuously pump the brakes in order to stop the vehicle. The vehicle was taken to the dealer where it was determined that the master cylinder and brake booster needed to be replaced. The failure and the current mileage was 42,000.

- Atlanta, GA, USA

Brakes failed due to faulty brake booster. Two others at the dealership had the same problem. Mazda could not immediately fix the problem because they are out of brake boosters and are not sure when any will be available. Indications are that this is a wide spread issue and should be investigated.

- Southlake, TX, USA

Brake system failure involving master cylinder and booster. Leaking internally. Replacement cost of $1500 researched CX9 and found this problem is widespread and not being addressed.we had a minor fender bender that could have been much worse. Mazda usa has not issued any bulletins as of yet.

- Naples, FL, USA

Catastrophic brake failure. Brakes would not stop vehicle. Vehicle towed for repair.

- Clifton Park, NY, USA

In June of 2012 I noticed that my brakes made a hissing sound at random times. I brought the car into the dealer for a complete service and brake check. I was told that the breaks were in perfect condition but they did do a brake flush. The hissing continued at random time until the week of 1/13/13 at which time the hissing was at every occasion the brakes were engaged. And on 1/15/13 the brakes failed to stop the vehicle. I brought the car directly into the dealership and was informed that it was a leak in the brake booster into the master cylinder. After researching this I have found that this is a common malfunction with the CX9 and I am extremely frustrated. Although Mazda acknowledged the issue on earlier models they are not acknowledging the issue on the later models. They should have to stand behind the parts and vehicles that they make. And when they know that a certain part or system has a history of failing they should take responsibility for the issue instead of making their customers pay for their mistakes and faulty parts.

- Ruskin, FL, USA

I have a 2010 Mazda Cx-9 with approximately 41,000 miles. I have been diligent in my maintenance-always with a Mazda dealer. The car started to exhale slightly when braking. The car then did not want to brake/stop without pumping the brakes repeatedly. I was able to stop suddenly but unable to stop without ample warning at stop signs, etc. The vehicle was taken to Mazda dealership where they told me that the vacuum booster and master cylinder were defective. I was not allowed to drive the car because it was not safe. They then told me the next morning that Mazda/dealership found no warranty covering such a malfunction/factory defect B/C I had passed the 36,000 miles mark. I will have to pay $839 for a repair to drive my car that is an issue with the manufacturing of my car. The dealer told me I must contact Mazda usa directly to see if they will pay for it-otherwise I am responsible. I have read other complaints and an article in the wall street journal both sitting the existence and experience of this malfunction. The NHTSA was said to be investigating the issue. Mazda should be forced to recall the vehicles and fix the malfunctioning brake system. It is not the fault of the consumer but of the car manufacturer.

- Los Angeles, CA, USA

The contact owns a 2010 Mazda Cx-9. the contact stated that while driving 25 mph, there was a delay in stopping distance once the brakes were engaged. The contact mentioned that he had to depress the brakes repeatedly in order to bring the vehicle to a complete stop. The vehicle was taken to an independent mechanic who diagnosed that the vacuum booster and master cylinder were defective and needed to be replaced. The manufacturer was not made aware of the failure. The vehicle was not repaired. The failure mileage was 50,000 and the current mileage was 50,040.

- Mira Mar , FL, USA