I live in [XXX]. On the way to [XXX], out of no where the car stopped accelerating. Was in eco mode at the time and dropped completely while trying to accelerate in the middle of the road. Pulled over completely turned off the car checked the engine nothing seemed out of the ordinary. Ran the diagnostics from the car and didn’t show any errors. Turned off again for a bit and turn on and everything was fine. Moved from eco to smart and turned around worked fine for about 5 m so we thought everything was on and tried to go back north to finish our trip and while on smart mode started to accelerate again and didn’t want to accelerate. Turned around and decided best to take it to dealership Monday. We have about another 1 hour to 2 hours to get home and it’s working fine in smart mode but it shouldn’t randomly drop acceleration at all in the middle of driving. Only at 16,487 miles. Doing it again only driving 33 m an hour and in smart mode. Not even going uphill just dropped acceleration while driving around town. About 15 m after. There’s still no error happening when it happens each time. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The vehicle began shaking and having ABS problems when driving at ~30 mph after having driven for several miles without issue. The vehicle did not have any history of problems or recent symptoms and was just over one year old. The vehicle was towed to the dealership. The dealership reported a broken driver side front wheel speed sensor wire and attributed it to rodent damage without other evidence.

Van made a loud pop noise and lost power. The HSG belt tensioner spring fell off it's seat loosing tension on the HSG belt. Was unsafe but luckily it happened before getting on the freeway, and coasted into a parking lot. Yes, it's at the dealership getting a replacement tensioner and belt. I believe so. No notification prior to failure, it was sudden.

On five separate occasions, while turning onto a high-speed roadway and attempting to accelerate to the flow of traffic, the vehicle suddenly lost the ability to accelerate. Despite pressing the accelerator, the vehicle would not exceed approximately 35 mph and then began to decelerate. During both incidents, a "Check Hybrid System" warning appeared, and I was forced to quickly pull over to the side of the high-speed road. The vehicle would only return to normal operation after it was turned off and restarted. This loss of power while merging into traffic created an extremely dangerous situation. Having three young children in the vehicle made the experience especially frightening, and I no longer have confidence that the vehicle can be relied upon to operate safely. Because this defect affects the vehicle's ability to accelerate safely in traffic, I am deeply concerned that it could result in a serious collision if it happens again. I took it into the dealership and the service center experienced the same issue. They thought they had resolved the issue and that it was a "one off" occurrence but it happened to me again just 3 weeks after the attempted repair. This time the engine light came on after the "Check Hybrid System" warning light.

I am filing this complaint to report a recurring, life-threatening safety defect in my 2025 Kia Carnival Hybrid involving the battery and hybrid propulsion system. This defect has occurred twice, and despite dealer repair attempts, it has not been resolved. On both occasions, while the vehicle was in operation, the hybrid system failed without warning. The vehicle displayed a hybrid system failure alert, lost the ability to accelerate normally, and became unable to maintain safe driving speeds. On the most recent occurrence, the sudden and unexpected loss of vehicle power created an immediate risk of collision. The vehicle’s failure while in traffic nearly resulted in a serious crash. I was driving with passengers at the time. The vehicle was taken to an authorized Kia dealership for repair following each incident. The same defect has now recurred after the first repair was completed, demonstrating that the underlying cause has not been identified or corrected. This defect substantially impairs the safety of the vehicle. The sudden loss of hybrid system function and propulsion while driving at road speed creates a direct and serious risk of accident, injury, or death to the vehicle’s occupants and to other drivers on the road. I am a [XXX] resident and am aware that this defect is not isolated to my vehicle. Numerous other 2025 Kia Carnival Hybrid owners have filed similar NHTSA complaints regarding battery failure and sudden loss of acceleration. I urge the NHTSA to open a formal investigation into this defect and to require Kia Motors America to issue a safety recall. I am currently too frightened to operate this vehicle and request urgent attention to this matter. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)