Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2011 Hyundai Sonata owners, lightly cleaned up (personal details are redacted by NHTSA).
A friend borrowed my car to go to the corner store to get me a couple of things while my husband was getting surgery. My friend ended up in a rollover accident after hitting a tree. All recalls were up to date on my vehicle, he stated that no airbags deployed. Now after the vehicle was rolled back over and taken to the tow yard the insurance adjuster was the first to see and the driver airbag had deployed. I was not there I cannot say when the airbag deployed however none of the curtain airbags deployed. Also my friend stated that the car accelerated just before impact he swerved to miss something in the road and ended up rolling the vehicle after hitting the tree. The car should not have been accelerating but it was like the car had a mind of its own. I thought the recall was to fix the air bags. He could have been killed.. no reason these cars are still on the road. …
While driving on the interstate, the car suddenly stopped accelerating even though my foot was still pressing the accelerator. I took my foot off the gas pedal and let the car coast for a moment, though the deceleration seemed faster than normal coasting, almost as if the brake was slightly engaged. When I pressed the gas pedal again, it started to accelerate for a moment but then the same thing happened and it felt like the brake was engaging and the car was slowing down even though I was still pressing the gas pedal. So I took my foot off again and tried this process several more times, and in the meantime moved to the right lane and put my flashers on because I could not get the car to go more than 30 miles per hour and I was nearly hit several times. I was about to pull over when the issue seemed to resolve itself just as quickly as it had started. …
I test drove the vehicle at an auction, watched several other people test drive the vehicle. Before the auction I test drove it one more time and put my obd scan tool on it to make sure there were no hidden codes or problems. I won the bid,and picked up the vehicle. I drove it approximately 6 miles from the auction and the falshing engine light popped on. I immediately pulled over in heavy freeway traffic. Put my scan tool on it and found out the knock sensor had triggered. The vehicle was shaking and making a terrible racket. It was inoperable in the worst possible spot on Highway 51 during rush hour traffic. I managed to slowing coast down the offramp and roll into a parking lot. I then called Purdy Hyundai and spoke with a service advisor and provided the VIN#. He (Vue Kue) informed me that the vehicle qualified for the recall and warranty work based on exactly that issue. …
The brake lights stay on all the time, thus preventing vehicles behind mine from knowing if I'm actually stopping. Hence, they may stop without reason, and endanger drivers behind them. The manufacturer has likely known of this being an issue in Sonatas from, at least, 2007 through 2013 models. The manufacturer is putting the task of solving the problem (if that's even possible), upon a dealer. And, my trip to that (nearest) dealership (75 miles away) creates its own danger. The danger is added to by a pre-existing unsolved issue of the horn not functioning. As per the brake light issue, I've been to the dealership about it twice, and they weren't even aware that the brake light switch they think attaches to my car doesn't. …
Even on a perfectly dry road, the cruise control can't be set and the traction control light comes on. The nearest dealer (75 miles away) said it was likely in need of a new brake light switch. That didn't solve the problem. Now, it is beyond the fact that the brake lights stay on whether the car is running or not. The brake light switch is clearly impacting various other functions and makes the car unsafe to drive, because vehicles following it conclude (incorrectly) that the driver is engaging the brakes. Additionally, if someone doesn't detach the battery cables when spending some time at a destination, they can be stranded as the result of a dead battery. …
in July of 2022 the buttons on the steering wheel like cruise control trip/reset button as well as radio controls eventually all quit working did not become fully aware of this until I was on the interstate and was driving with the cruise control set and when I needed to turn off cruise control it wouldn't turn off by the steering wheel thankfully I know can hit the brakes and the car will shut it off however after this all happened the air bag light came on and stayed illuminated I called my dealer and they insisted that there was no recall on the CLOCK Spring in the steering wheel of my car and wanted me to pay out of pocket for an issue that they claim was non existint as well them also telling me all the recalls were taken care of when I purchased the vehicle in novemember of 2020 and im only the second owner had the car for 3 months and Hyundai stated that my vehicle had the knock …
When my car is turned on there is a very noticeable shake coming from the engine area. It's not that bad once the car is driving. However, I was driving 40 miles an hour when my check engine light came on, then I was unable to accelerate and my car stalled (it's an automatic car).Once my car started up again, the check engine light was flashing, and I could only drive at like 15-20 miles per hour for my speed. Made it to O'Reilly and had them run the check engine light codes for me and it popped up with the P1326 code regarding the knock signal range/performance. I recently got a check engine light code for a p0449 EVAP vent control valve (it wouldnt allow me to pump gas into the car). I'm unsure if the issues are related but wanted to provide all the details.
This is a 'Stop Lamp Switch' issue. The car will randomly turn on the ABS light causing the ABS system to engage and not allow you to use the accelerator pedal. This is very dangerous as if you are about to merge on or off a highway the car does not allow you to correctly control your speed. This issue happens more prevalently at night time when the full beam headlights (auto or manually turn on when dark out), which is very concerning. This issue has been going on for a year now and no mechanics at Hyundai can fix or diagnose. It happened again to me this morning and came very close to causing an accident as I could not engage the accelerator pedal on a turn. Please, in the interest of safety and saving lives fix this dangerous defective part issue.
My car had engine seized while driving on the road with no warning light prior nor other mechanical issues. When the engine seized, all mechanical powers are have lost power including brakes and power steering in which have almost caused a near accident at an early morning rushed hours. The vehicle's odometer reading at 120,836 and was up to date on all normal tune up performances. Other issues that have arise after purchasing the car are: warning light came on for airbag, real loud clunking sound on roof when hitting a bump on the road and engine will not start because of fuel line system issues. Cruise control had also stopped working after a year of purchased.
My engine keeps making a knocking sound. When I am driving it will reduce speed, and begins to idle while already driving. Which concerns me that these same issues occurred on my same year, make and model on my vehicle and some how Hyundai dealership will tell me that my car does not have a recall. 470,000 cars of the same year make, and model went in for exactly what my car is doing.
NHTSA investigations
Throttle control system vulnerabilities
The Office of Defects Investigation (ODI) of the National Highway Traffic Safety Administration (NHTSA) received a petition letter dated October 10, 2021, requesting an investigation of possible defects in the electronic throttle control (ETC) system on certain Kia vehicles resulting in the opening of DP21-003.
Acceleration complaints in other Sonata years
Frequently asked questions
How common are acceleration problems on the 2011 Hyundai Sonata?
NHTSA has 95 complaints about the speed control & acceleration of the 2011 Hyundai Sonata, 3% of the model year's 3,378 complaints. The component named most often is cruise control (2 mentions).
Is there a recall for 2011 Hyundai Sonata acceleration problems?
No. NHTSA lists no speed control & acceleration recall for the 2011 Hyundai Sonata, though it has 14 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2011 Hyundai Sonata acceleration problems start?
Half of the complaints with a recorded mileage happened before about 60,000 miles, and 26% before 25,000 miles.
Is it dangerous?
Owners linked 18 crashes, 1 fire and 9 injuries to speed control & acceleration problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.