Mazda CX-9 brake failure problems

Filed Feb 11, 2026 · Driver assistance · WA · crash · 1 injury

On February 9, 2026, our 2023 Mazda CX‑9 experienced a sudden and complete system malfunction while being driven. Multiple system failures began approximately six minutes before the crash. During this time, the driver reported: • Total loss of steering • Complete brake failure • No response to acceleration or driver input • No ability to slow, stop, or maneuver the vehicle • No meaningful warnings that allowed corrective action The vehicle became completely uncontrollable. At the crash site, there were no skid marks, no braking evidence, and no signs of evasive action, consistent with a full loss of vehicle control. The vehicle only stopped after entering approximately two feet of water and striking a tree. The vehicle was declared a total loss. This incident represents a severe safety defect involving critical electronic and mechanical systems. A modern vehicle should not lose all steering, braking, and control functions under any circumstances. We are requesting a full investigation into the cause of this failure and whether similar incidents have occurred in other Mazda vehicles. We can provide photos, crash documentation, diagnostic information, and driver statements upon request.

Filed Aug 12, 2023 · Brakes · GA

Brakes stopped working while we were on vacation. Made the drive down fine, but the next day went to drive the car, pressed the brakes and the car did not come to a complete stop. Also made a funny noise when we tried to press on the brakes. My husband practically had to stand up and push all the way down to get car to stop. Luckily we were not in a congested or confined place. Ended up replacing the brake booster. Three weeks later my acceleration stopped working intermittently. I go to press the gas and the car doesn’t go. The dealership is saying it’s the brake signal.

Filed Feb 20, 2023 · Brakes · NJ

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 federal safety agency, 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.

Filed Oct 3, 2022 · Brakes · OH

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. Mazda should have done a recall in 2014, not an extended warranty. Although Brake Boosters are supposedly good for at least 150,000 miles of driving, our brake failure at around 83,000 miles proves otherwise. the federal safety agency should order Mazda to recall all vehicles with the defective brake part and replace them at Mazda's expense, probably hundreds of dollars each time. We do not want to have our brake booster replaced by our regular Euro Motosports mechanics because a recall must typically be repaired by the dealer. We already filed a complaint with State of Ohio Attorney General's office, but their people say the complaint must first go through BBB. No urgency on their part at all, even when informed potentially fatal flaw in the brakes. To avoid dangerous accidents, the federal safety agency should act more swiftly. Thanks.

Filed Aug 2, 2022 · Brakes · 115,000 miles · NC

The contact owns a 2008 Mazda CX-9. The contact stated while driving approximately 30 MPH, he noticed that the brakes felt loose and the braking distance had become extended while attempting to stop the vehicle. The contact stated that he heard a hissing sound while depressing the brake pedal. The contact stated no warning light was illuminated. The contact stated that the brakes failed completely while attempting to stop for a traffic signal and the vehicle rolled into the intersection. The contact had taken the vehicle to a local dealer, where it was diagnosed that the brake booster was malfunctionin,g and needed to be replaced. The vehicle had not been repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 115,000.

Filed Oct 23, 2021 · Brakes · RI

Brakes failed while driving. Mazda dealer did not fix this known defect under recall SSP93

Filed Oct 6, 2021 · Brakes · CA

Brake Booster damaged. I ended up with no brakes and nearly crashed.

Filed Apr 29, 2021 · Brakes, Engine · 110,000 miles · TX

Tl* the contact owns a 2012 mazda cx-9. The contact stated while driving at various speeds, the vehicle stalled. Additionally, the brakes failed to engage when the brake pedal was depressed. There was no warning light illuminated. The vehicle was taken to an independent mechanic to be diagnosed. The contact was informed that the brake master cylinder and brake booster needed to be replaced. The contact was advised to reach out to the dealership eldorado chevrolet(233 n central expwy, mckinney, tx 75070). The contact wanted a second opinion and the vehicle was taken to eldorado chevrolet (2300 n central expy, mckinney, tx 75070) where it was also diagnosed with the master cylinder and brake booster needing to be replaced. The svc mgr informed consumer he wouldnt advised anyone to drive the vehicle until repairs were made. Due to incorrect title work the dealer refunded some money and took posession of the vehicle. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 110,000. The consumer stated the vehicle was put back on the lot for resale. The consumer contacted a lawyer and vehicle was taken off the lot but carfax was not updated with correct information.

Filed Nov 4, 2020 · Brakes · 129,000 miles · CT

Tl* the contact owns a 2012 mazda cx-9. The contact stated that while driving at approximately 20 MPH, the brakes failed to operate. The contact mentioned that the brakes gradually slowed down the vehicle and stop independently. The vehicle was taken to an independent mechanic where they informed the contact that there was an unknown recall on the vehicle. The contact contacted riley mazda (75 myrtle ave, stamford, ct 06902, (203) 978-5780) and was informed that the VIN was not under recall. The contact was informed of an extended warranty coverage however, the mileage had been exceeded. The manufacturer was notified of the failure. The approximate failure mileage was 129,000.

Filed Oct 22, 2020 · Brakes · 84,894 miles · GA

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.