2015 Hyundai Sonata electrical problems

Filed Oct 28, 2026 · Brakes, Electrical · CO

On Wednesday, October 21, 2026, our 2015 Hyundai Sonata with the 2.4L Theta II GDI engine suffered a sudden, complete engine seizure while traveling about 75 mph on I-25 Southbound near Castle Rock, CO. A family member was driving. Warning lights across the car began flashing, the engine made a loud grinding noise, and the brakes stopped working. Over a long distance, the driver was able to get the car onto the shoulder and bring it to a stop, then engage the parking brake. There was no collision and no injuries, only because traffic was light. The car was towed to a repair shop, then transferred to a second shop, which determined the engine had seized and requires full replacement. This vehicle is covered by Hyundai's Theta II GDI engine campaigns for connecting rod bearing failure. On October 26, 2026, Hyundai told us the Knock Sensor Detection System software update (Campaign 953) was never completed on this vehicle and declined coverage. Neither we nor the prior owners, who are family members, recall receiving any notice of this campaign. All previous check engine lights were diagnosed and repaired at independent shops, including an intake manifold replacement in April 2024, and no shop ever identified an open engine campaign. A full engine seizure at highway speed, combined with the loss of braking, creates a serious crash risk for the driver and surrounding traffic.

Filed Aug 6, 2026 · Electrical, Fuel system · MA

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.

Filed Jul 16, 2026 · Electrical · FL

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.

Filed Mar 10, 2026 · Electrical · 223,718 miles · MI

Odometer Fraud. The contact purchased a 2015 Hyundai Sonata. The vehicle was a private sale. The vehicle was purchased on March 1, 2026. The mileage at the time of the purchase was 41,486. The vehicle was taken to the dealer, where the contact was informed that the odometer mileage was last reported at 223,718. The seller was not made aware of the discrepancy.

Filed Mar 4, 2026 · Electrical, Engine · CT · fire

I was driving on the highway and the engine shut off but everything else remained on. I drifted to the breakdown lane and turned the car off. It would not start again and the car began acting up by turning lights on and off, telling me to check the tire pressure, and not unlocking the doors. I then saw some very light smoke from the engine compartment. I popped the hood and looked and saw a glow on the bottom side of the engine area. Then the car just went up in flames.

Filed Jan 19, 2026 · Brakes, Electrical · MS · 1 injury

My 2015 Sonata will stall out dropping speeds to 12-24 when i slightly merge, when I turn ect. Then it won’t accelerate for what seems like 10 minutes realistically 2 minutes maybe 3 Then will slowly regain speed. I’ve almost wrecked twice Share care with daughter and she’s been victim to it way way more. This is scary and Hyundai won’t stay behind their product Local dealership won’t fix recalls so we have to go over 120 miles for repairs. The recall isn’t even for transmission engine

Filed Dec 16, 2025 · Electrical, Engine · GA

i've had my 2015 hyundai sonata now for A year. i took it to the hyundai place to have recalls on the security fixed. and told them about the valve cover gasket leaking. they said they fixed it. however every since i took it to the dealership i have had nothing but problems. my car makes a rattling noise when i accelerate, i smell a strong gas smell occasionally at random times but always while driving. my driver brake light has never worked, my driver headlight keeps blowing, my airbag light is now coming on randomly, my car has a bag vibration while going down the road, when i let off the gas it stops and i have replaced tires and still it won't go away no matter what i have done to fix it , and there has been many times after i return home the smell of something burning as off something is on fire is coming from my car. i have even been in panick thinking something today home was on fire but the smell was coming from my car. and others have even stated they smelled it as well. i've already taken out two loans to fix the valve cover gasket and the fuel pump filter, i can not keep taking out loans to fix problems that appears to be problems from the manufacturer and same problems others have had due to malfunctioning issues. i have children that ride in my car, i would hate for someone to get hurt or worse bc of manufacturing problems. then hyundai would have a bigger problem on their hands.

Filed Dec 2, 2025 · Driver assistance, Electrical · FL

My 2015 Hyundai Sonata has a defective engine. The motor failed unexpectedly even though the car has low usage and has always been maintained properly. I was informed that many Hyundai engines from these years came with manufacturing issues, and mine appears to be one of them.

Filed Nov 27, 2025 · Electrical, Engine · IL · fire

While I was driving at approximately 55mph, a loud clank happened and the car stalled, and smoke started pouring out of the hood and through the vents into the cabin, and I was leaving burning pieces behind on the road. I pulled over, ran to the back to get my dogs out of their crash tested kennels in the backseat, and both rear doors & passenger front door were locked. I ran up front to unlock them, and the unlock button did not work. I tried the unlock on the keys and it did not work. Due to having a recommended crash safe kennel set up it was not possible to crawl into the back to open it from the inside. My dogs were trapped in a car that was filled with smoke and on fire for over 2 minutes while I debated breaking the windows. I managed to fish a wire into the back to unlock and pull the door open from the inside of the back doors. The car stopped burning but was still smoking for several minutes after & I was able to clear the smoke to make it safe for my dogs to wait for a tow. When the mechanic looked at it he said the engine blew up due to the rod shattering into the block, destroying the entire engine and spilling oil which lit on fire. Mechanic recommended I contact Hyundai for engine replacement as this was a known issue with other 2015 Hyundai sonatas which were recalled due to risk of a defect rod knock causing the rod to shatter causing high speed stalling. Hyundai says my engine was not included in that specific recall. I included photo of the shattered rod which fell out when the mechanic lifted the vehicle

Filed Sep 22, 2025 · Acceleration, Electrical · GA

The engine light started to come on and go off and when I got the codes ran, it said something along the line of misfire. I had the spark plugs changed and I kept regular maintenance done on oil changes and tune ups. Now my engine is knocking and the vehicle is in limp mode.