Mazda CX-5 adaptive cruise problems

Filed Nov 1, 2026 · Driver assistance · TN

I own a 2026 Mazda CX-5 (Premium Plus) experiencing critical, cascading safety defects involving the vehicle's telematics and driver-assistance systems. I have video evidence of the defect. Unintended Acceleration / Adaptive Cruise Control Failure: While using the Mazda Radar Cruise Control (MRCC) with Stop & Go in traffic, the system silently drops tracking of the lead vehicle (the cluster icon shifts from active green to white without warning or audio alert). Failing to recognize that traffic ahead is still stationary, the vehicle commands unexpected acceleration toward stopped cars, creating an immediate collision hazard requiring manual braking. Inoperative Emergency SOS System: The vehicle's in-cabin SOS Emergency Call (eCall) button is completely inoperative and malfunctioning due to internal telematics communication failures, disabling critical emergency response capabilities. These concurrent failures of active safety controls and emergency communication systems present a severe risk to public safety. The vehicle has already undergone multiple software updates and repair visits with no resolution.

Filed Oct 12, 2026 · Acceleration, Engine · CO

My 2017 Mazda CX-5 has experienced a recurring condition more than six times involving sudden jerking, rapid deceleration, and loss of normal accelerator response during extended highway driving, often while cruise control is engaged. On multiple occasions the engine has also shut down. On 09/11/2026, while traveling south on I-35 at approximately 80 mph with cruise control engaged, the vehicle suddenly began jerking violently and rapidly losing speed. Normal accelerator response was lost and a vehicle behind me nearly struck my vehicle. I was able to reach the shoulder just before the engine shut down. The vehicle would not restart and required towing. There was little or no meaningful warning before the loss of power. The vehicle was inspected by a Mazda dealer. I specifically reported the recurring highway jerking, deceleration, loss of throttle response, and shutdown concern. An aftermarket OBD-II device was removed after the dealer identified parasitic battery draw. The dealer subsequently stated in writing that the battery and alternator were healthy and that the vehicle was “operating as intended.” On 10/09/2026, with that device no longer installed, the same symptoms occurred again during highway travel and the vehicle again became disabled and required towing. The Mazda dealer has now verified the drivability concern and reported a Fuel Rail Pressure Sensor “A” Circuit Low fault and low fuel pressure. The dealer is recommending replacement of the high-pressure fuel pump as an initial repair, followed by further testing of the in-tank fuel pump. The vehicle is currently available for inspection at the Mazda dealer. the federal safety agency’s VIN lookup currently shows 0 unrepaired recalls. I am reporting this because sudden loss of acceleration and power at highway speed creates a serious collision and roadside safety risk.

Filed Sep 2, 2026 · Brakes, Driver assistance · PA

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.

Filed Jun 16, 2026 · Electrical · 91,000 miles · IL

The contact owns a 2016 Mazda CX-5. The contact stated that while driving 70 MPH with the cruise control activated, the cruise control cancellation switch failed to operate as intended after several attempts or while depressing the brake pedal. No warning light was illuminated. In addition, the contact was able to deactivate the cruise control using the main cruise control power switch. The vehicle was taken to a local dealer to be diagnosed; however, the cause of the failure was not yet determined. The vehicle was not repaired. The manufacturer was made aware of the failure by the local dealer. The failure mileage was approximately 91,000.

Filed Jun 3, 2026 · Driver assistance · FL

My 2025 Mazda CX-5 includes a Traffic Jam Assist (TJA) stop and go feature. This feature allows the adaptive cruise control to move the vehicle in traffic with minimal drier intervention. As traffic advances the vehicle moves. If traffic stops, the vehicle stops. When clear of vehicles based on the set safe space setting in the adaptive cruise control, it resumes the predetermined speed set in the adaptive cruise control. The problem: While in "traffic jam assist" (TJA) mode, if changing lanes L or R to a lane that has vehicles farther away (clear lane), the cruise control radar/camera then sees a clear opening and begins accelerating to the predetermined speed on the cruise control. However - at this time the system fails to recognize a that another vehicle is farther ahead. maybe 4 or 5 car lengths ahead, and continues accelerating dangerously close to the next vehicle (I cannot say if it will stop or not because I have intervened to apply the brakes), cannot risk a rear end to another vehicle.The system fails to recognize that another vehicle is present after a lane change has occurred and braking or slowing as expected does not take place. This is a common repeatable scenario. The failure to recognize another vehicle after changing lanes is a serious and dangerous problem that should not be taking place. This poses an accident risk from an automated system that has a inherent flaw in its logic/design. the federal safety agency should investigate this system and determine what corrective action can be taken to prevent a collision while using this system.

Filed May 6, 2026 · Driver assistance · MD · crash

On October 16, 2025, while slowly pulling into a parking space, my vehicle experienced sudden and unintended acceleration without driver input. I did not depress the accelerator. Despite attempting to stop the vehicle, I was unable to do so. The vehicle mounted the curb, entered the sidewalk area, and struck a community mailbox, a tree, and two legally parked vehicles. My vehicle and the two parked vehicles were declared total losses. At the time of the incident, pedestrians, including toddlers, were present on the sidewalk. This loss of vehicle control created an immediate and severe risk of serious bodily injury or death. Post-incident diagnostics indicated multiple system errors, including but not limited to: •Powertrain Control Module •Anti-lock Brake System (ABS) •Instrument Cluster •Smart Brake Support / Mazda Radar Cruise Control Of particular concern is that Mazda, through its authorized dealer Rosenthal Mazda of Gaithersburg, Maryland, had prior notice of abnormal vehicle behavior. On two separate occasions before the crash, I reported that the vehicle would jolt suddenly, as if struck from behind, and at times felt as though it was attempting to accelerate without input. On each occasion, I was informed that the dealer could not duplicate the issue. No corrective action was taken, and the vehicle was returned to service. This event constitutes a serious safety failure involving unintended acceleration and apparent braking or electronic control system malfunction in this-model vehicle. Given the involvement of advanced driver assistance systems and braking components, this matter warrants immediate and thorough review.

Filed May 3, 2026 · Acceleration, Brakes · WI

2021 Mazda CX5 AWD- Non Turbo Engine. Sunny Day, Dry. My Car was clean. No Precipitation. Some shadows of the interstate light poles across the road 200-300 feet in front of me, but they were thin shadows. Sun Was to my Left. I was driving South on May 01 2026 about 10am on the Interstate going Highway Speeds, with adaptive cruise control "on", in the 2nd lane of a 4 lane interstate. Thankfully no other traffic ahead or behind me. Car slammed on the brakes suddenly, pretty hard. I counteracted and added more gas pedal to keep in going. I turned off the Cruise Control. After a while I re-engaged the Cruise Control and had no issues. This could have been a huge accident in busier traffic. Will get the car checked out at Mazda Dealership Service this week.

Filed Apr 7, 2026 · Acceleration, Brakes · 24,000 miles · OH

The contact leased a 2024 Mazda CX-5. The contact stated that the yellow electronic emergency brake light was displayed. The cruise control and rear brakes were inoperable. The brake pedal was pulsating while depressed. There was smoke coming from the front brakes. The vehicle was taken to a local dealer, who replaced the brakes, and the module was inoperable, but the failure recurred. The vehicle was taken to three independent mechanics, who determined that the rear brakes were firm. The manufacturer was contacted, and a case was opened. The failure mileage was approximately 24,000.

Filed Feb 27, 2026 · Acceleration, Driver assistance · PA

I purchased a 2019 Mazda CX-5 (As is) on July 20, 2015. On September 11, 2025, as I was traveling on a three lane highway. I attempted to pass another vehicle. As I was attempting to go around the vehicle, my Mazda suddenly began braking and quickly losing acceleration. The speed limit on the highway was 70 mph. I estimated my speed at the time was between 70 and 75 mph as I attempted to pass. Pressing on the accelerator pedal did nothing. I had to try and very carefully steer the car to the right hand side of the road while trying to avoid oncoming traffic approaching from behind. When I finally got the car off the road, this is when I noticed that the car had stalled. The car started right back up and I continued to my appointment. The "radar cruise control" was activated at the time of the incident. On September 15, 2025, I contacted the dealer where the car was purchased and explained what happened. I was asked to bring the car in that same day. The car was supposedly looked over and connected to the Service Dept.'s computer to see if any error sign appeared. Nothing showed up. I service technician was then asked to ride with me to see if the car would replicated the same stalling as it has previously done. We could not get the car to stall as it had previously done. Before leaving, a salesman asked me if I wanted him to explain the "radar cruise control" to me some more. I agreed. The salesman then proceeded to tell me that "the car did not stall, it was simply braking from the activation of the radar cruise control". Being an experienced driver, I told the salesman that the car had stalled as evidenced by the fact that I had to restart it. The situation was not resolved to my satisfaction, but no other offers were made by the dealer. I requested additional diagnostic work to be done, but the dealer refused to cooperate. I did take the car to another Mazda dealer, but could get no offer but to connect the car to their computer.

Filed Jan 6, 2026 · Transmission · 140,000 miles · IN

The contact owned a 2020 Mazda CX-5. The contact stated that while driving under 45 MPH, the TCM received a false data sensor warning, causing the vehicle to enter LIMP Mode. The contact stated that during the failure, the smart brake feature, Adaptive Cruise Control, and other unknown ADS features and warning lights were illuminated. The contact stated that the failure with the ADS system prompted the vehicle to come to a complete stop while driving 45 MPH. The contact parked and turned off the vehicle to troubleshoot the ECU after the failure had occurred. The contact restarted the vehicle, and the adaptive cruise control warning light, smart brake feature, and ADS radar features returned. The vehicle was not repaired. The manufacturer was notified about the failure. The failure mileage was 140,000.