What component or system failed: The hybrid battery management system (BMS) failed while driving. The dashboard displayed a Battery Management System error along with a lane assist warning. The vehicle then completely lost propulsion, no response from the accelerator pedal, while on an incline, causing the vehicle to roll backward down the hill. The vehicle is currently at the dealership (Kia Temecula) and available for inspection but no one has reached out to me for days. Safety risk: The vehicle lost all forward propulsion while in motion on a hill and began rolling backward, with no ability to accelerate or control forward movement. This posed a serious risk of collision or rollaway accident. I shut the vehicle off and restarted it, which restored partial function for approximately 1 minute before the same failure recurred. Has the problem been reproduced/confirmed: Not yet confirmed by dealer — vehicle was towed to Kia Temecula on 7/12/26 via Kia roadside assistance and is awaiting diagnostic inspection. Dealer scheduling offered August 4, 2026 as the earliest availability, which is unacceptable given the safety nature of the defect. Inspected by manufacturer, police, insurance, etc.: Not yet inspected. Vehicle towed to authorized Kia dealer; diagnostic pending. Warning lamps/messages prior to failure: Yes — Battery Management System error and lane assist function warning appeared on the dash immediately before the vehicle lost propulsion. No prior symptoms were noted before this incident.

While driving our 1 month old car we intermittently heard a loud clap sound, we assumed it was due to it being a hybrid vehicle. Well on Wednesday we were merging on to the freeway at approx 20 mph when we heard an extremely loud bang and the 3rd window imploded. There was nothing that hit the car, no point of origin for any foreign object, but rather an implosion. How was your safety or the safety of others put at risk? This happened within inches of my child's head and terrified my child. Has the problem been reproduced or confirmed by a dealer or independent service center? We immediately assessed the vehicle was not safe to drive and filed a complaint with Kia Corporate and called the dealership we purchased it from to be assessed and repaired. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? It is currently at the dealership. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? The only oddity was the intermittent clapping sound we heard randomly over the past few weeks of driving our new van.

Hello there - I am a fairly new owner of a KIA carnival hybrid 2026. I leased the vehicle in March'26. I have about 2200 miles put on the vehicle. On XXX at around 11am I was driving the vehicle on the left lane of freeway at ~65 mph and there was a sudden flash of Engine Maintenance service light and the vehicle cut out power to the accelerator pedal and started to bring the vehicle to a stop. This is in the fastest lane of the freeway while there was cars behind me. Luckily there was space to stop on the left side of the lane and I parked my car with the EMS light still on. Mind you that cars were going past me at 65+ mph. This is a major safety concern. I switched off the vehicle and turned it back on and the check engine light was still on but I was able to drive the vehicle to an exit and return home. I had the vehicle switched off for a few hours and when I turned it back on, the check engine light was gone. I scheduled a service at the dealership I purchased and explained the situation, they checked the codes/logs and test drove the vehicle and returned the vehicle back to me saying they cannot duplicate the issue. Whether the issue is resolved or not, I am majorly concerned that the diagnosis is incomplete and this issue can happen anytime on a freeway which is a safety hazard. This should not be happening on a brand new vehicle. I have raised a complaint to KIA corporate as well. There are a lot of other users companing similar issues: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I am reporting an intermittent but serious safety issue with my Kia Carnival involving the backup camera system. Since approximately May 2026, the rear backup camera has failed more than 10 times. When the issue occurs, the display will either: Show a completely blank screen, Flicker repeatedly, or Turn into a solid green screen. Once the failure begins, it continues even after repeatedly turning the vehicle off and back on. The system only starts working again after the vehicle has remained powered off for several hours. This is a significant safety hazard because when the backup camera fails, the parking assist system/sensors also stop functioning. As a result, while reversing, I lose both the camera view and the audible/object detection assistance. This substantially increases the risk of backing into a pedestrian, child, cyclist, or another vehicle, especially in parking lots and residential areas. The problem has occurred more than 10 times over the past several weeks. I have taken multiple videos clearly documenting the failures, including the blank screen, flickering display, and green screen. I have brought the vehicle to the Kia dealership for inspection. However, because the problem is intermittent and could not be reproduced during their inspection, they stated that they were unable to diagnose or repair the issue. Despite this, I have video evidence demonstrating the recurring failure. This appears to be an intermittent electronic or software defect affecting a critical safety system. A backup camera is an important safety feature intended to help prevent backover crashes. The simultaneous loss of both the camera display and parking sensors creates an unacceptable safety risk. I respectfully request that NHTSA investigate this issue to determine whether it represents a broader defect affecting Kia Carnival vehicles and whether a recall or other corrective action is warranted before this defect contributes to a serious injury or fatality.

I own a 2026 Carnival Prestige SX Hybrid and having loss of propulsion problems. After much research, and absolutely no help from KIA, I now think my problem is my foot, size 15, is too large to safely drive this vehicle. My shoe intermittently depresses the brake ever so slightly while I accelerate from a stop. This triggers the Brake-Throttle Override which temporarily cuts propulsion power. The BTO is in all US cars but of the five vehicles (2025-26, different manufacturers) I have driven this past six months, this is the only one that has given me concern for my safety! KIA claims the vehicle is operating as expected! I claim that they have engineered the brake and acceleration pedals too close to each other creating a serious safety issue for those of us with larger foot sizes. The owners manual makes no mention of the BTO function nor how to restore propulsion once the BTO has been activated! While all US vehicles have the BTO function, they vary as to how the function performs. In KIA, once the BTO is triggered, all propulsion is suspended! The BTO was designed to prevent runaway acceleration. In this KIA, they have created a new safety problem because they failed to allow enough space for larger footed individuals room to safely operate their vehicle! KIA needs to introduce a foot size requirement for all prospective buyers or redesign the area around the accelerator and brake pedal so safety is no longer an issue!