Hyundai Sonata Complaints (2015)

1,208 consumer complaints on file.

#11756074August 10, 2026
ENGINE
My Hyundai Sonata engine stalled out while driving on the highway. I had it towed to a dealership with the hope they would fix the issue because it was supposed to be covered under warranty from a recall. The dealership said the engine replacement would be covered as long as they got approval from Hyundai. Hyundai apparently only asked that specific dealership for the service records that they had, didn’t even reach out to me or try to find any other service records on the vehicle and denied the claim for “neglect of maintenance” because that dealership only had records from 0-90,000 miles. The dealership got back to me and told me the news and I told them that I will get all service records from 0 miles to current. I got all those records together and sent them to the dealer. A week later they called and said Hyundai was again going to deny my request because of the same “neglect of maintenance” which isn’t true based on the records I have and they have. I have driven the vehicle less than 10,000 miles and there has been nothing wrong with it. No check engine lights ever and regular oil changes.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755866August 10, 2026
ENGINE
The contact owns a 2015 Hyundai Sonata. The contact stated that while driving on several occasions at various speeds, the vehicle lost power, and the check engine warning light was illuminated. The vehicle was taken to a dealer where it was diagnosed that the engine had failed and needed to be replaced. The vehicle was repaired, but the failure reoccurred within a year. The vehicle was taken back to the same dealer where it was diagnosed and determined that a software update was needed. The vehicle was repaired, but the failure persisted. The vehicle was then taken back to the same dealer, and there was oil on the pistons and a tune-up was needed. The vehicle was repaired, but the failure persisted. The vehicle was taken back to the dealer, where it was advised that an oil consumption test could not be provided until the pistons had failed. The manufacturer was notified of the failure, and a complaint was filed. The failure mileage was approximately 88,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755594August 8, 2026
ENGINE
Vehicle: 2015 Hyundai Sonata VIN: [XXX] Mileage: ~85,000 Description of the Problem: While driving, the vehicle suddenly began producing thick smoke from under the hood without warning. I safely maneuvered to the shoulder to avoid an accident. The engine subsequently seized completely and became inoperable. My mechanic diagnosed this as a known internal manufacturing defect in the Theta II engine (connecting rod bearing failure), a widely documented issue for this model and production year. Oil and coolant levels were confirmed normal with no leaks, ruling out maintenance neglect. I initially paid for an unnecessary starter replacement before this diagnosis was confirmed. This is a serious safety hazard that could cause loss of engine power and control while driving, posing a risk to myself and other drivers on the road. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
Yes
Injuries:
0
Deaths:
0
#11755188August 6, 2026
ENGINE
Since the 9C2 update on June 24, 2026, my vehicle has not driven the same. I'm experiencing clunky or harsh gear changes at low speeds, especially during stop-and-go driving. When I slow down and then accelerate again, the vehicle sputters or hesitates before responding. While driving at lower speeds, I also feel intermittent skips or small surges, almost like bubbles or brief misfires. These symptoms were not present before the 9C2 update, and they have noticeably affected the drivability of the vehicle. It was suggested the transmission needed time to "relearn" driving patterns, but it has been several weeks with no change
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755317August 6, 2026
ELECTRICAL SYSTEM, FUEL/PROPULSION SYSTEM, UNKNOWN OR OTHER
1.) Following Hyundai's 9C2 Campaign update for the ECU that was completed back on May 27th, 2026, my 2015 Sonata went into limp mode [solid check engine light present] while I was accelerating up an on-ramp on the 2nd drive cycle since the update was performed. I was already far away from the dealership so I was forced to limp it to my local shop that I regularly use to have it checked out. It was confirmed that the code on the vehicle was P200A for intake manifold runners. Since the update was for smog regulation, the code was cleared in order to see if it would come back. Since then, it has not, however the vehicle continues to have one persistent problem. The RPMs will dramatically dip and then surge back upwards while the car is coasting (no gas and no brake applied). 70% of the time, you can feel the car violently jerk as it appears to try and correct itself. 2.) I've brought this car to multiple dealerships, have a case open with corporate and have also found that this is a systemic issue with this specific update in these cars. All and all, nothing has been done. I'm repeatedly turned away over and over again because their techs are only permitted to look into it once they have hard evidence of a fault. In this case, that would be a dashboard light. I'm told that I may only return if the check engine light comes back, which as I mentioned previously, posed a HUGE safety risk to myself the first time it appeared. If I can only go 55mph down the highway, I am at risk of being rear-ended or struck in some way. 3.) The problem has not been reproduced by the dealer as they will not test drive it to see the dip and spike. However, the code was still pending for awhile in the vehicle before it cleared it on its own, so that was acknowledged by at least one place. 4.) Vehicle has not been inspected by anyone but a dealership and local mechanic. 5.) No other signs prior to the vehicle limping out on me other than some acceleration concerns on May 27th, 2026.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755077August 5, 2026
ENGINE
Engine / Short block assembly / Connecting rod bearing seizure. The engine suffered a sudden, catastrophic seizure while I was actively driving on a steep incline mountain road with a cliff on one side and forest on other. The vehicle experienced an immediate, total loss of motive power, forcing an emergency maneuver onto the shoulder in 5 seconds with no power steering or power brakes, creating an extreme collision hazard on a high-speed incline. The rod bearing melted due to a manufacture defect and could have also possible caught fire in heavy fire country. The fuel pump was also leaking recently and just replaced. They are nearly $1800 for a new pump because of price gauging because they are in "high demand". The Check Engine Light was solid (not flashing) for a thermostat code (P0128) due to extreme internal friction/heat from the failing bearings. There were no flashing KSDS warnings or physical signs of engine overheating. My car was denied a new engine under a Federally Mandated Warranty explicitly stating the exact symptoms of internal engine defect that happened in my car under "owner neglect" even though I have changed my oil regularly and even before the manufacture recommended time frames to do so. I've changed the valve covers, 02 sensors, thermostats, and plenty more on this car than any other car I have ever owned proving I'm actually an exceptional owner. I remained nice to all corporate staff during this process while they denied my car proper care under a Federal Mandate. I bought this car to believe that Hyundai was a superior company in regards to warranties, price, and function as opposed to the more expensive counterparts of the same class. Which in the end has cost me way more, and almost my life. This car is dangerous and the company has done everything in their power to try to cover it up while placing blame on the very consumers that are believing in them to do better.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754721August 4, 2026
ELECTRICAL SYSTEM
The Hybrid system kept crashing ! Triggering the auto theft and would not connect to fob , told it was immobilzer, and/or shortage in EV battery!!!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754029July 31, 2026
ENGINE
Driving vehicle at slow speed crossing an intersection and engine completely shut down. The engine has completely seized and needs replaced due to a known recall. I have only owned the vehicle for 7 months. Hyundai is refusing to pay for engine replacement claiming a previous recall prior to me owning the vehicle should have been completed. I only drove the vehicle 1,000 miles in that time at nothing over 50 mph. There was no notification to me about this recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753510July 29, 2026
STRUCTURE:BODY, UNKNOWN OR OTHER, VISIBILITY/WIPER
I was driving my 2015 Hyundai Sonata approximately 35 mph after leaving the Hyundai dealership following an engine replacement when the hood unexpectedly flew completely open without warning. The hood struck the windshield, completely obstructing my forward visibility and creating an extremely dangerous situation. I was able to safely pull over without causing a collision, but the vehicle sustained extensive damage and was declared a total loss by my insurance company. During the same service visit in which the engine was replaced, the dealership recommended replacing the hood latches, but I declined that repair. Hyundai later informed me that the hood latching system was functioning properly after the engine replacement and that the vehicle passed its post-repair inspection and road test. Approximately one mile after leaving the dealership following the engine replacement, the hood unexpectedly opened while I was driving. There were no hood-ajar warnings, warning lights, or other indications that the hood was not properly secured before the incident. The sudden loss of visibility created a serious risk of a crash that could have resulted in severe injury or death. I am submitting this complaint because I believe this incident represents a significant vehicle safety issue that should be investigated.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753166July 27, 2026
AIR BAGS, UNKNOWN OR OTHER
We are the sole owners of the 2015 Hyundai Sonata. Over the years the dashboard has deteriorated and developed cracks along the entire length, including over the area of the passenger airbag. We are currently concerned as to what would happen in the event of an accident that would trigger the air bag causing the dashboard to explode and send splinters all over the place, possibly causing severe damage to the passenger. I took the vehicle to Lehman Hyundai and they could not give me a definitive answer as to whether this was a dangerous situation or not. They gave me an oral estimate of $3,500 just for the part, and who knows what the labor costs would be. Whether I end up donating, gifting or selling the car, I am truly concerned about the safety of this vehicle and the condition it is in.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11750940July 16, 2026
ELECTRICAL SYSTEM
This vehicle had a recall, 201, for the smart junction box. This was due to the blinkers not working properly. The software update was performed, however, the problem still exists. This was due to the smart junction box. Now, aside from the blinker issue, the ac stays on when the engine is turned off, lights come on by themselves, the media screen goes randomly into night mode, daylight running lights are constantly in night mode, smart junction box failure. I have not taken this to a mechanic as of yet, the dealership is aware, and I opened a case with Hyundai case #42940056, however, I have not received a call from my service advisor or Hyundai. They offered to do diagnostics, but, if these problems are not about the safety recall, I would have to pay $350 for diagnostics, unless I get the problem fixed by them. This car has 66k miles with a new engine installed at 59400 miles! At this point, I have the car parked, battery disconnected, and looking for the most efficient way to fix the problem, which must be performed by specialized equipment.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11750143July 13, 2026
ENGINE
On June 22, my 2015 Hyundai Sonata suddenly lost all electrical power without warning. The vehicle stalled and would not restart. There were no warning signs beforehand. After the incident, the car had no electrical power and was inoperable. Further inspection determined that the engine had failed and required replacement. I maintained the vehicle with regular oil changes and was unaware of Hyundai’s Service Campaign 953 (KSDS update). I was never notified that this campaign needed to be completed, and I believe that failure to receive notice contributed to Hyundai’s denial of my engine replacement claim. I purchased the vehicle December 19, 2019. I was never notified by the dealer or manufacturer
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749467July 10, 2026
ENGINE
I had the Service Campaign 9C2 and TSB 25-01-087H recall emissions update performed. I immediately noticed degraded performance with my vehicle. It's very jumpy/stuttery after I first start driving and feels less responsive. Even after driving for a bit, it feels like it drives and shifts oddly. It is not as smooth as it used to be. My car drove fine prior to the update and immediately felt different after the update. It's now been over a week and it's still like this, so it's not the engine computer adapting or something like that.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749278July 9, 2026
ENGINE AND ENGINE COOLING
The contact owns a 2015 Hyundai Sonata. The contact stated that while operating the vehicle, exhaust fumes were noticed inside the cabin, and the check engine light illuminated before the engine stalled. The vehicle was towed to a local dealer. The cause of the failure was not determined. The manufacturer was notified of the failure. The failure mileage was unknown.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749309July 9, 2026
ENGINE AND ENGINE COOLING
The contact owns a 2015 Hyundai Sonata. The contact stated that the vehicle was taken to a local dealer who performed an emission software upgrade. Later, while driving, the air conditioner blew hot air, the thermostat increased to high, and an engine overheating warning message was displayed on the instrument panel. The vehicle was taken back to the dealer, who diagnosed that the thermostat had failed and needed to be replaced. The thermostat was replaced, and the failure was remedied. The manufacturer was notified of the failure. The failure mileage was 74,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11748832July 7, 2026
ENGINE
Engine misfiring and low compression
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11748575July 6, 2026
ENGINE
Oil consumption
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11748280July 4, 2026
POWER TRAIN
VEHICLE: 2015 Hyundai Sonata, 2.4L Theta II GDI engine Mileage at time of incident: [ 93k Date update performed: June 2026 Dealer/location where update was performed: Fitzgerald Hyundai Gaithersburg, MD DESCRIPTION OF PROBLEM: After my vehicle received the ECM software update issued under Hyundai Service Campaign 9C2 (ECU Software Update for Theta II Emissions Improvement, TSB 25-01-087H / 26-01-013H-1), the vehicle began exhibiting noticeable jerking/hesitation during acceleration that was not present before. For this vehicle this happens consistently after a cold start then does not happen again.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11746404June 25, 2026
POWER TRAIN, ENGINE
The incident began following a routine maintenance visit on March 16, 2026, and has been a continuous, ongoing safety hazard every single day since. While the vehicle was in for routine brake service and an oil change, the dealership automatically applied an open, manufacturer-mandated ECU S/W Update THETA II (26-01-013H-1) under Service Campaign 9C2 Emissions (Code NP001-SC9C2) without my prior knowledge of its drivability side effects. This software flash directly compromised the vehicle's powertrain logic, creating two notable, daily safety failures. First, within the first 5 minutes of engine startup, and most pronounced on every cold engine startup, the throttle delivery is highly erratic, causing uncommanded low-speed surging. In a specific incident in a parking lot following a cold start, I accelerated to approximately 15 MPH and completely removed my foot from the accelerator pedal to coast. Instead of slowing down, the vehicle unexpectedly lunged and pulled ahead forcefully against my intent. Second, even after reaching full operating temperature, the vehicle completely loses safe and predictable engine braking at greater speeds; when lifting off the gas pedal, engine RPMs aggressively drop, causing the vehicle to coast freely as if in neutral. Re-applying the accelerator causes a violent "phantom shifting" downshift and a hard transmission lockup. My safety and the safety of others are put at risk every time the vehicle is driven. The low-speed throttle surging creates an ongoing risk of hitting pedestrians or cross-traffic, while the permanent loss of predictable engine braking drastically extends stopping distances. No warning lamps or diagnostic trouble codes (DTCs) appeared prior to or during these continuous failures. The vehicle remains available for inspection.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11743649June 12, 2026
ENGINE
On October 2024,I brought the car in to RickCase Hyundai for maintenance and to address an oil leaking issue. I texted the service advisor, “Please do not do the oil change till you find out where the oil is leaking”, I’m replacing it frequentlyWhen I picked up the car and inquired about the leaking, the he told me that there was not an issue. January 2025, the car was driving rough again, noticed the oil low and filled it up. February 2025 driving on 595, The car stopped. I had it towed to Rick Case, they told me I needed to replace the piston. I said no this has to do with the oil consumption issue that I brought the car in October that you never addressed. The four new spark plugs that were put in were burnt on the tips. They went through the warranty issue to get the engine repaired and it was denied. I said this is not a warranty issue. This was a mistake on your part because you never address the oil consumption issue in October 2024. As of June 12,2026, the dealership still has my car. When I call and ask, What’s going on with my car. The only response I get is we are trying something else it’s going to take some time. Last summer, the service advisor told me he was going to fix my car, wanted me to come pick it up and drive it for 1000 miles and bring it back. They couldn’t fix the car. They never offered a loaner. The vehicle suffered a catastrophic engine failure and completely stalled in the middle of a live road, creating an immediate highway safety hazard. the vehicle is still being held at Rick Case Hyundai Weston for over a year regarding excessive oil consumption issues, which the dealer failed to resolve. The vehicle has 85,000 miles and a complete maintenance history. Hyundai Corporate is currently denying a replacement engine under the active engine settlement framework, leaving a known stalling safety hazard unresolved."
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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