Hyundai Sonata Hybrid adaptive cruise problems

Filed Aug 30, 2026 · Brakes, Driver assistance · CA · crash · 2 injuries

I was driving through a high school pick-up line where traffic was moving slowly. My vehicle was operating on adaptive cruise control, and I had my foot resting on the brake in case I needed to stop. A woman was about to cross the street, so I tapped the brakes. The vehicle did not slow down as it should have and instead began accelerating. I immediately pressed down on the brakes as hard as I could, but the vehicle continued accelerating and did not respond to my braking. There were vehicles stopped in front of me, so I attempted to steer around the vehicle directly in front of me to avoid a direct collision. The vehicle continued forward and collided with two other vehicles before coming to a stop after striking a wall. Based on what I experienced, both the adaptive/assistive cruise control and the vehicle’s braking response failed during this incident. Prior to the incident, the vehicle had been operating normally, with no warning lights, error messages, or other symptoms indicating a problem. Police and paramedics responded to the scene. I was not issued a citation. A police report was completed, and my insurance company, dealership, and lien holder have been notified. There were multiple witnesses to the incident. The vehicle remains available for inspection at the tow yard listed above.

Filed Sep 21, 2025 · Engine · MA

The engine shut off on the highway on two different days. Vehicle was going between 65 and 70 mph. The vehicle engine shut down and all the warning lights came on. Every one. The vehicle still moved but nothing inside worked, it ran on battery mode for the 17 miles to the dealership with a maximum speed of 60 mph. The risk was the immediate unresponsiveness of the vehicle and the sudden and immediate reduction in speed and power. It presented itself twice in about 2,000 miles. The dealership charged a 491$ diagnostic and found all the warnings and reset it, not reason for it happening and sent me on my way. Then it happened again. Brought back to the dealership and they tried to say they did another diagnostic and called the tech helpline. It took hours and they still don’t have a definitive answer, wanted to try almost 2k in repairs to see if it would fix the issue without any guarantees it would. Warning lights, all of them came on, cruise control, abs, engine light blinking, steering, literally everything and messages started running through the information center.

Filed Oct 27, 2024 · Airbags, Brakes · CT

When outside temperature drops, car starts in morning with several warning lights illuminated, indicating fault with several safety systems including airbags, brake, power steering, front camera, blind-spot collision warning system, traction control and smart cruise control. Car key fobs have consistently failed, disabling access to the vehicle. The vehicles 12V reset recently failed which required Hyundai Roadside Assistance (10/25/24). According to BlueLink application, cars 12V battery has been reset dozens of times, which is information visible to the service centers. However, at several past service appointments it has been verbally stated that "problem can not be replicated" and was not documented. Problem was confirmed by Hyundai service center on March 13, 2024. Problem was not resolved at the time of service, vehicle was returned back without resolution. With temperatures now dropping at night, said issues are occurring daily with warning indicators for failing safety systems illuminating upon cold start and electrical system failing daily.

Filed Aug 31, 2024 · Engine · TN

This is the seventh occurrence of complete loss of power while driving on the interstate. The hybrid system warning activated, followed by the engine shutting down, and all dashboard lights illuminated with alerts indicating "Shut Off Engine/HEV." An 18 wheeler was pulling out from the shoulder as I was losing power and barely missed getting crushed. The former problems have all been at interstate speeds with similar accident avoided. The service history clearly demonstrates that Hyundai has repeatedly attempted to address this issue by replacing numerous critical components, including the engine, transmission, knock sensor, battery (three times), integrated brake actuation system, and smart cruise control, among others. Despite these extensive repairs, the problem persists. On this latest occasion, less than 4,000 miles and four months since the last major incident, the dealership has proposed replacing the intake manifold, EGR valve, HSG belt, and spark plugs. The belt was changed less than 20K miles ago. and I believe the spark plugs were as well. Each time my vehicle experiences this issue, it is out of commission for weeks or even months at a time, causing significant inconvenience and raising serious safety concerns. I no longer trust this vehicle and I don't believe the many recalls have successfully addressed the root cause of issues with the 2017 Hybrids.

Filed Feb 22, 2023 · Driver assistance · MA · crash · 2 injuries

The forward collision warning, automatic emergency braking and adaptive cruise control failed as the first 2 activated when there were no oncoming collisions in front of me and the nearest cars around me were 1/4 of a mile away. The cruise control failed as it turned back on after the vehicle veered off the highway and into the rest stop. My safety and the safety of a lot of other people in the rest stop were put at risk because the system malfunction and tripped when no other cars were present that would have led to a collision. The vehicle led me off the highway into the rest stop where others could have been fatally hurt. I ended up with a shattered left foot that required a major reconstructive surgery to mend but the break will affect me the rest of my life, with more problems developing later on in life as well. No one inspected the vehicle or listened to what I had to say. No investigations were launched by insurance, the manufacturer or the police. If anything, insurance and the manufacturer seemed like they were in a hurry to dispose of the vehicle, urging me to release vehicle where it was sent to after the crash to one of insurance centers. The collision warning light came on and the vehicle responded by hard braking and veering to the right, then the cruise control turned back on and accelerated into the rest stop, first bouncing up the curb and onto the dirt, hitting a sign on the passenger side then bouncing off a tree on the driver side and finally T-boned a parked boat on a trailer head on. The vehicle was a total loss

Filed Dec 5, 2019 · Acceleration, Brakes · 39,000 miles · WI

While driving on the highway, a notice was shown on the dashboard that the hybrid system and cruise control system were no longer functional. The vehicle then started to accelerate, uphill, without the gas pedal being engaged. The vehicle was taken off the highway and when coming to a near complete stop the vehicle stopped working completely. After restarting the vehicle and driving it to a safe place to park a notice indicated the breaks were no longer functional. The car was subsequently towed. The vehicle has had numerous repairs since and is still experiencing the same issue(s) as of 12/05/2019.

Filed Jun 14, 2019 · Engine · 94,000 miles · AR

Tl* the contact owns a 2011 hyundai sonata hybrid. While driving 75 MPH with the cruise control engaged, the contact heard an abnormal noise. The contact stated that the vehicle began to decelerate and failed to accelerate when depressing the accelerator pedal. The contact parked the vehicle onto the side of the road and turned off the engine. The contact checked under the hood and noticed coolant leaking. The vehicle was not able to be driven and was towed to an independent mechanic. The contact called orr auto mall russellville (located at 3115 e main st, russellville, ar 72802, (877) 742-3331) and notified them of the failure. The vehicle was not diagnosed or repaired. The manufacturer was notified. The failure mileage was 94,000.

Filed Jan 29, 2019 · Electrical, Seat belts · TX

Tl* the contact owns a 2016 hyundai sonata hybrid. The contact stated that the front driver and passenger seat belts failed to properly retract and loosen when necessary. The seat belts restricted the breathing and bodies of the front seat occupants when the seat belts were secured. In addition, the vehicle lunged, jerked, and accelerated on its own. The failure was more prevalent when the eco and cruise control functions were activated. Eckert hyundai, inc. (4011 s interstate 35, denton, tx 76210, (940) 243-6200) stated that the eco and cruise control functions failed and provided an interim repair of disconnecting the battery to clear the ecu and ECM codes, which affected the transmission. Another dealer (james wood hyundai, 2110 us-287, decatur, tx 76234, (940) 627-4600) asked the first dealer to test drive the vehicle to generate the codes. The second dealer advised the contact not to drive the vehicle with the eco function activated. Both dealers stated that if the transmission was the cause of the failure, it may be replaced under warranty. The vehicle was not repaired. The manufacturer was notified of the failures. The failure mileage was not available.

Filed Dec 14, 2017 · Acceleration · 39,000 miles · CA · crash

Https://youtu.be/z4thv5a3lrk dynamic cruise control that stops and starts in bumper-to-bumper traffic is what sold me on this car. Lamentably, I did not know hyundai excludes aeb from hybrid ltd ultras. As the video shows, frantic beeping from the forward collision warning system was not accompanied by any braking at all. I slammed on them too late. I was in dcc mode when the warning sounded. Dcc can gradually slow from freeway speed to a stop and resume, but fcw apparently cancels dcc's braking! This must be no more than a difference in software between gas-only and hybrid ltd ultras because all sensing and control hardware are identical. Hyundai's response to my inquiries are just repetitious confirmations of what I already discovered the hard and expensive way.

Filed May 23, 2016 · Engine · 69,000 miles · TX

My vehicle blew a piston rod while I was driving down the highway on cruise control doing 2000 RPM's. I have always kept up on the maintenance with this car but when I had it towed to the dealership they are saying that it was my fault. They do have an open recall on my year, make, model and engine size but not my VIN. I have done my research online and I have found other cases like this. The car only has 69,000 miles on it.