NHTSA complaint #11761780

Owner complaint summary

On 09/01/2026 at approximately 55 mph, I was driving with adaptive cruise control engaged. The vehicle ahead decelerated abruptly. My vehicle began braking hard with no input from me for a fraction of a second. A red BRAKE warning appeared in the instrument cluster with an audible alarm. I then applied the brake pedal hard. On first contact the pedal barely moved from its rest position and was extremely firm. About a second into my application, while still traveling at over 25 mph, pedal resistance dropped sharply and pedal travel increased substantially. I had to push the pedal several inches farther to get back to comparable deceleration. The pedal did not pulse or vibrate. I came to a matching speed roughly one car length from the vehicle ahead, and only because I kept braking hard. I did not see an MRCC Cancelled message, though the BRAKE warning occupies the same part of the display, so I cannot say whether the initial deceleration came from Mazda Radar Cruise Control or Smart Brake Support. No brake, ABS, or DSC warning lamp illuminated before, during, or after the event, and none has since. There were no symptoms beforehand, and the brakes have worked normally since. Failed component: unknown. I cannot determine whether the change in pedal feel came from the brake booster, the DSC hydraulic control unit, the master cylinder, or the driver assistance system handing brake control back to me. The vehicle has not been inspected by anyone and no service center has reproduced the issue. The vehicle is available for inspection if needed. If a driver assistance system is commanding brake pressure and withdraws it during the driver intervention, total deceleration can drop at the moment when the driver still wants to stop aggressively to avoid a crash. Suddenly, the driver has to find the extra pedal travel while still closing on the obstacle. I slowed to a safe speed in time. With less room, or less attentiveness, I may not have been able to.