2015 Hyundai Sonata: adaptive cruise control problems

Filed Sep 20, 2025 · Brakes, Electrical · FL

The rubber stopper for the brake light switch on the brake pedal deteriorated and fell apart. This resulted in the brake lights remaining on constantly, cruise control being disabled, and low battery voltage.

Filed May 12, 2025 · Acceleration, Brakes · IL · crash

My 2015 Hyundai Sonata has demonstrated multiple instances of unintended acceleration and braking failure: April 20, 2024 – While idling in a drive-thru line, the vehicle suddenly lurched forward without any attempt to accelerate and crashed into the vehicle in front of me. I was unable to stop it. This resulted in the other car being totaled. I took it to a Hyundai dealership afterward, but they found no definitive cause. April 4, 2025 – My daughter was driving and attempted to stop at a red light. Despite applying the brakes, the car did not stop and continued through the intersection, striking the door of another vehicle. May 12, 2025 – Today, while using cruise control set to 55 mph, the car began accelerating beyond the set speed without input. It appears the cruise control system is malfunctioning and not disengaging as expected. The vehicle currently shows no open recalls, but I found that similar issues were previously investigated under the federal safety agency action DP21003 for this model year. These incidents occurred months apart, but the behavior is consistent and extremely dangerous. I am requesting a formal investigation. The safety of my family and others on the road is at risk.

Filed Sep 6, 2023 · Acceleration, Engine · 92,000 miles · GA

The contact owns a 2015 Hyundai Sonata. The contact stated while driving approximately 30 MPH, the sunroof detached from the roof of the vehicle. The cause of the failure was not yet determined, and the vehicle was not yet repaired. The vehicle also experienced severe engine knocking and the vehicle was taken to the local dealer who diagnosed that the engine was faulty and needed to be replaced. The engine was replaced, and the vehicle was repaired. In addition, several safety features including the Lane Departure, Cruise Control, and the Forward Collision Avoidance system intermittently malfunctioned. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure. The failure mileage was approximately 92,000.

Filed Aug 23, 2023 · Brakes, Transmission · FL

I would like to write about my experience with New Port Richey Hyundai. I have owned a Hyundai Sonata Hybrid Limited since 2015. I take immaculate care of my car and it only has 65,000 miles. All maintenance has been done regularly and on time. For the last six months I have had a warning light and alarm going off for a few seconds once in a while, which shuts off my cruise control. I took the car in, in the spring of 2023 to have the codes read and no problems were found. Finally, In July of 2023, while my wife was in traffic it started again and totally shut off the car. Unfortunately, the brakes did not work as well. She was going up a slight incline and was able to come to a stop. The brake pedal went completely to the floor. The warning was about a Hybrid System Failure. It was very upsetting to her that her brakes failed when the Hybrid system had a problem. This should never happen! Once the car was towed to New Port Richey Hyundai in Florida, we were told that the car would be look after. The car was returned in the middle of July 2023 with a new electric motor installed. Everything was working fine until today, August 23, 2023. The same warning light that I brought the car in for in May 2023 is going off again. It only stays on for a second or two, so I don’t have time to read it. I really hope this car does not shut off again with no brakes when traveling on the interstate. As mentioned before the car has low miles and is well cared for. This should not be happening.

Filed Jan 16, 2023 · Driver assistance · NC

Forward collision warning is frequently inaccurately sensing collision even when no other vehicles are on the road. I am now afraid to use adaptive cruise control because I fear sudden breaking especially when merging lanes.

Filed Jun 5, 2022 · Engine, Transmission · OH

Was driving with cruise control on and driving close to 70mph and the RPMs shot up passed 5 then the car jerked and my speed had went from 70 down to 50 and 40 the cruise controle turned off on its own and the car lost power but was still on but it just wouldn't drive passed 2 rpms and the check engine light was flashing so I turned around and headed the opposite direction so I could get the car off the road then it made this loud noise sounded like throwing metal inside a metal bladed fan and then the car shut off and hasn't started since. The car did not over heat or have any smoke coming from it.

Filed Nov 3, 2020 · Acceleration, Driver assistance · IA

When trying to set my cruise control a message pops up on my dash saying scc conditions not met.

Filed Aug 29, 2020 · Acceleration · 34,600 miles · OR

Cruise control does no always engage

Filed Jun 6, 2018 · Fuel system · 30,000 miles · MN

1) gas tank never takes more than 15 gallons of gas when the gas tank was supposed to hold 18 gallons. One day the fuel computer showed the range as 15 miles and the gas tank still took only 15 gallons from the pump even when the car gets a mileage of more than 30 mpg. Also, the pump abruptly stops in between and I have to restart pumping the fuel. This is either a fuel guage problem showing the gas tank is nearly empty when its really not or a gas tank problem. Online research indicates that multiple people have this problem. 2) the adaptive cruise control is really jerky and slams the breaks suddenly and accelerates abruptly resulting in a very jerky ride.

Filed Jun 1, 2018 · Acceleration · 2,500 miles · NV

While driving at 70 MPH on the highway with adaptive cruise control operational, the vehicle failed to respond on 3 different occasions to the sudden and unexpected presence of a vehicle that unsafely moved into my traffic lane just feet ahead of my vehicle. Instead of my vehicle backing off, my vehicle was moving closer and closer to the car ahead and I had to apply the brakes in order to avoid crashing into the vehicle in front of us. It was as if the adaptive cruise control system was unable to "see" situations when confronted with vehicles that suddenly appear in front of my vehicle and are extremely close. In all other respects, that adaptive speed control system worked perfectly.

Filed Nov 9, 2017 · Acceleration, Fuel system · 60,000 miles · NM

1. Cruise control is jerky and rough on acceleration and deceleration 2. Main issue I have with this car is that the fuel gauge is incredibly inaccurate. If it reads at 1/8 tank, I can only put in 12-13 gallons. Each "tick" mark on the gauge value ranges from about 9 miles to 63 miles despite the fact that it regularly gets 32+ mpg combined city/highway. When I complained to the dealership (I bought it used) they replaced the vaccuum cylinder, which helped with filling the tank (it would previously just shut off mysteriously during fill-ups) but then the gas gauge measured even worse. The "range" as calculated by the car's computer is always very low and drops off precipitously even though I know (by the trip meter) that I haven't gone far enough to have used as much gas as it would appear. Despite the obvious flaws of the gauge, the codes still read that it is working "normally" and to have it covered by the warranty, I have to experience a complete failure of the fuel sending units, I.e. Catastrophic break down. I would like to have them replaced before it gets to that point.

Filed Jan 26, 2017 · Driver assistance, Electrical · 15,030 miles · NJ

I was driving at 6:20 am on the new jersey turnpike. I was in the left lane and going approximately 70 MPH using the scc (smart cruise control). All of the sudden, the lights start flashing and the car completely turns off. Since it was before sunrise, everything was black and I couldn't even see where I was driving, not to mention that the steering wheel became locked. 10 seconds later, the care came back to "life". It did that same intro with the "system check" thing as it does when the car is started from a park position- only I was on the highway going 70 MPH. I have never heard of something so absurd, but I guarantee that if this was during rush hour or a busier time during the day- there would have been a major accident!