Jul 14, 2026Electrical systemEngineFuel system
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!
NHTSA ODI 11750230
Jul 13, 2026Fuel system
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.
NHTSA ODI 11750056
Jul 1, 2026Electrical systemFuel system
2026 Kia Carnival Hybrid – Purchased 9/5/2025 Mileage: 8,450 April 2026- While driving over 60 mph, the vehicle's acceleration failed. A "Hybrid Failure" warning appeared on the dashboard, and the vehicle quickly decelerated. I had seconds to safely cross 3 lanes, and the vehicle had to be towed. The vehicle was at the dealership for 13 days, during which no problem codes were reported, and diagnostic scans appeared normal. No safety feature or diagnostic system reported this failure! I was told to take the vehicle because they had nothing to fix without a diagnostic report. May 2026- I drove the vehicle for a few weeks before this occurred again, with the same warning and complete deceleration. The vehicle was brought to a 2nd dealership, nearest to this incident. They have had the vehicle for 29 days with no safety or diagnostic issues to report and no ability to duplicate the problem. During this occurrence, my daughter was able to video the dashboard and deceleration from the passenger seat. I have provided this video to KIA. The national KIA team is refusing a buy-out option for this vehicle after my family and I have repeatedly been put in danger on the road. It also puts drivers around us in danger as we frantically attempt to proceed to safety while quickly decelerating. It is also extremely alarming that the safety systems and diagnostics do not show that these problems are occurring. While the local dealership has been understanding and professional to date; however, the National brand and its refusal to put safety first, especially on a brand-new vehicle, is unacceptable. We can provide the video and any other documentation you would like. We will be engaging with an attorney after Kia National declined our buyback
NHTSA ODI 11747779
Jun 5, 2026BrakesFuel system
I had pickup my vehicle from the dealership where it had been since the 29th of May due to a previous incident exactly the same as what occurred this time. The vehicle had been returned to me as the service department could find nothing wrong from the May 29th incident. On my way home from the dealership, the vehicle started the same as on May 29th. When accelerating from a stoplight, I lost all propulsion. After about 60 seconds the vehicle recovered and I turned to go back to the dealership. At the aforementioned intersection (crossing over I35) it again lost propulsion, only this time for a longer period of time. I was in heavy traffic and the car behind me was honking even though I had my hazard warning flashers operating! I made it to the dealership where the service manager agreed to do a ride along. We were about to the end of the ride along when the vehicle lost propulsion power. It wasn’t as severe and recovered quickly. The service manager said he had noticed the brake pedal move at the time I accelerated. His theory was that the brake being applied at the same time as the acceleration cause the computer to get confused and it’s reaction was to remove propulsion. No offer was given to take the vehicle back for further testing. I dropped the service manager off and proceeded to return home, being cognizant of my foot placement and insuring it was well away from the brake when accelerating. KIA Care has so far refused to get involved. While I recognize braking at the time of acceleration is counterproductive, it should not cause a catastrophic propulsion failure. Plus the system sets no flags that it had this event! I have tried recreating this failure by using my left foot on the brake while accelerating with my right. This doesn’t recreate the problem so it must be a timing issue. I do not know if this issue is unique to my vehicle or is shared with other hybrids! If KIA Care refuses to investiga, the lemon law might have to be invoked!
NHTSA ODI 11742376
Apr 29, 2026Speed controlFuel system
-A "Check Hybrid system. Stop safely. " warning has come on 7 times now. The vehicle loses power and slows down abruptly before coming to a complete halt. This has happened on railroad tracks, the highway, and an intersection where my wife and children were almost hit by other motorists. The dealer has not been able to reproduce the code, but we have pictures and videos of said incidents. The vehicle has been inspected by Kia technicians and "fixed" multiple times, but this keeps happening and I will not risk my family's lives any longer. There has been zero warning every time this system failure has occurred. We are undergoing a buyback process with Kia corporate and are prepared to take legal action under Georgia state lemon laws. Thank you for your time.
NHTSA ODI 11734512