2026 Kia Carnival Hybrid Problems

I am writing to formally express my serious concern and disappointment regarding my Kia Carnival Hybrid. Shortly after purchasing the vehicle, with only approximately 6,000 miles on the odometer, the vehicle suddenly stopped operating while I was driving on the freeway. This created a dangerous situation for my family and other motorists. The vehicle had to be towed to an authorized Kia dealership for diagnosis and repair. No warning or message had appeared before the issue. The dealership retained the vehicle for approximately one week and informed us that a PCB (Printed Circuit Board) component had failed and needed to be replaced. After the repair was completed, we were assured that the issue had been resolved and that the vehicle was safe to drive. Unfortunately, after driving only about 50 additional miles, the exact same issue occurred again. The vehicle once again became inoperable, leaving us stranded and raising significant concerns about the reliability, safety, and quality of this vehicle. We towed the vehicle on 6/22/26 and Kia dealership had it till today 8/7/26 and corporate keep saying they working on it but unresponsive.

Detailed information is in the attached pdf file, but in a nutshell, Kia is covering a safety defect in their vehicles by claiming the process is “proprietary”. On several occasions we have lost propulsion, which means we had no control over our vehicle, and Kia’s explanation is simply, “the vehicle is performing as intended “! These incidents always happened at low speeds, just accelerating from a stop, but left us in a precarious situation as we were left in the middle of a busy intersection with no control over our vehicle! Propulsion would eventually return. After surviving several of these failures, I learned the proper thing was to let both pedals return to their idle position and then the vehicle would recover. This is a most difficult thing to accomplish when surrounded by angry drivers! The failures were identified by Google AI as a Brake Override System, also known as Brake Throttle Override. However, Kia already has a very functional Brake Over Accelerator process, so why would they have two similar functions? Kia knows the answer but is refusing to divulge any information regarding the intention or purpose of this mysterious process which makes our vehicle unsafe!

I am writing to formally express my serious concern and disappointment regarding my Kia Carnival Hybrid. Shortly after purchasing the vehicle, with only approximately 6,000 miles on the odometer, the vehicle suddenly stopped operating while I was driving on the freeway. This created a dangerous situation for my family and other motorists. The vehicle had to be towed to an authorized Kia dealership for diagnosis and repair. No warning or message had appeared before the issue. The dealership retained the vehicle for approximately one week and informed us that a PCB (Printed Circuit Board) component had failed and needed to be replaced. After the repair was completed, we were assured that the issue had been resolved and that the vehicle was safe to drive. Unfortunately, after driving only about 50 additional miles, the exact same issue occurred again. The vehicle once again became inoperable, leaving us stranded and raising significant concerns about the reliability, safety, and quality of this vehicle. We towed the vehicle on 6/22/26 and Kia dealership had it till today 8/7/26 and corporate keep saying they working on it but unresponsive.

Detailed information is in the attached pdf file, but in a nutshell, Kia is covering a safety defect in their vehicles by claiming the process is “proprietary”. On several occasions we have lost propulsion, which means we had no control over our vehicle, and Kia’s explanation is simply, “the vehicle is performing as intended “! These incidents always happened at low speeds, just accelerating from a stop, but left us in a precarious situation as we were left in the middle of a busy intersection with no control over our vehicle! Propulsion would eventually return. After surviving several of these failures, I learned the proper thing was to let both pedals return to their idle position and then the vehicle would recover. This is a most difficult thing to accomplish when surrounded by angry drivers! The failures were identified by Google AI as a Brake Override System, also known as Brake Throttle Override. However, Kia already has a very functional Brake Over Accelerator process, so why would they have two similar functions? Kia knows the answer but is refusing to divulge any information regarding the intention or purpose of this mysterious process which makes our vehicle unsafe!

While driving on an interstate during a heavy summer thunderstorm, the vehicle suddenly displayed a warning stating, "There may be a problem with the Battery Management System," along with a "Check Hybrid System" message. At the same time, the check engine light illuminated and the hybrid system stopped functioning without any prior warning. Approximately 10–15 minutes before the incident, I had driven through approximately 4 inches of standing water on a surface street at a speed of about 25 mph. After entering the interstate and traveling at approximately 65 mph in heavy rain, the hybrid system suddenly disabled itself. Cruise control was not engaged at any point during the trip. Immediately after the warning appeared, the vehicle experienced a significant loss of power and entered what appeared to be a reduced-power (limp) mode. The gasoline engine continued to run, but acceleration was severely limited, making it difficult to maintain speed or accelerate with surrounding highway traffic. This occurred at night, during heavy rain, on a busy interstate.The unexpected reduction in power created a hazardous situation and increased the risk of being struck by other vehicles while attempting to merge or pull over. After I was able to safely stop and restart the vehicle, the "Check Hybrid System" and Battery Management System warning messages disappeared. The vehicle has approximately 6,000 miles and was purchased new. This vehicle is used to transport my family, including my wife and our three young children. I believe this presents a significant safety concern because the sudden loss of power occurred without warning while traveling at highway speed in adverse weather conditions. Even though the vehicle remained drivable, the reduced acceleration made it difficult to safely maintain traffic flow or move to the shoulder, increasing the risk of a collision. I request that this issue be investigated to determine whether there is a defect affecting the hybrid system.

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 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!

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.

I am writing to formally express my serious concern and disappointment regarding my Kia Carnival Hybrid. Shortly after purchasing the vehicle, with only approximately 6,000 miles on the odometer, the vehicle suddenly stopped operating while I was driving on the freeway. This created a dangerous situation for my family and other motorists. The vehicle had to be towed to an authorized Kia dealership for diagnosis and repair. No warning or message had appeared before the issue. The dealership retained the vehicle for approximately one week and informed us that a PCB (Printed Circuit Board) component had failed and needed to be replaced. After the repair was completed, we were assured that the issue had been resolved and that the vehicle was safe to drive. Unfortunately, after driving only about 50 additional miles, the exact same issue occurred again. The vehicle once again became inoperable, leaving us stranded and raising significant concerns about the reliability, safety, and quality of this vehicle. We towed the vehicle on 6/22/26 and Kia dealership had it till today 8/7/26 and corporate keep saying they working on it but unresponsive.

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!

Detailed information is in the attached pdf file, but in a nutshell, Kia is covering a safety defect in their vehicles by claiming the process is “proprietary”. On several occasions we have lost propulsion, which means we had no control over our vehicle, and Kia’s explanation is simply, “the vehicle is performing as intended “! These incidents always happened at low speeds, just accelerating from a stop, but left us in a precarious situation as we were left in the middle of a busy intersection with no control over our vehicle! Propulsion would eventually return. After surviving several of these failures, I learned the proper thing was to let both pedals return to their idle position and then the vehicle would recover. This is a most difficult thing to accomplish when surrounded by angry drivers! The failures were identified by Google AI as a Brake Override System, also known as Brake Throttle Override. However, Kia already has a very functional Brake Over Accelerator process, so why would they have two similar functions? Kia knows the answer but is refusing to divulge any information regarding the intention or purpose of this mysterious process which makes our vehicle unsafe!

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!

The floor railings above the battery, that allow the second row seats to slide, get hot. Extremely hot to the touch. Burning my children’s feet. Not sure if it’s related but the a/c does not stay cold when driving long distance and the HV battery just died last month for no reason. Brand new car.