2015 Hyundai Sonata service brakes problems

“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…”

“I have the 2015 Hyundai sonata with the 2.5 GDI engine that eventually will seize due to internal damaged caused by manufacture design flaws. My Hyundai threw a P0010 code which causes my car to idle high and causing low vacuum affecting my brakes. I had a diagnostic test done at a Hyundai dealership that told me it was a cvvt cam sprocket issue and that it was the beginning of the end of the engine, They quoted me 3700.00 but the engine was to far gone and this repair would only accelerate the engine to seize. They said since the engine isn't seize Hyundai will not cover the cost to repair or exchange the engine, I contacted the Hyundai customer service who stated since the repair that is needed wasn't the root cause of the problems associated with the engine swap warranty they were not going to help me even though I explained to them that the cars high accelerating and the braking system been jeopardized and been told the engine is beyond repairs I feel Hyundai should reconsider their decision and help a loyal customer. I have purchased 12 Brand New Hyundaj since 2001. The customer Representative was Extremely un Professional even suggesting I scrap my car,…”

“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”

“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.”

“The car has had an electrical issue ever since taking to to get a recall around may of 2023. It will randomly brake and shift the transmission badly while downshifting. I feel as if my make and model falls under the theta II campaign they had to replace certain engines for having a knocking rod be fault and release shaving into the engine causing it to misfire. Not only that but the electrical issue is completely random it happens atleast once or twice a week. It had began ever since I took it for a recall, and when I took it back they found no issue and left food in the back of my car and the chairs leaned back. This was the Fontana Hyundai dealership”

“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 NHTSA 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.”