2019 Hyundai Sonata engine problems

“The contact owns a 2019 Hyundai Sonata. The contact stated that while driving 55 MPH, the check engine warning light illuminated, and the vehicle went into LIMP Mode. The contact stated that the vehicle failed to accelerate above 58 MPH. The contact retrieved DTC: P1326 (Knock Sensor Detection System) at O'Reilly Auto Parts and stated that the knock sensor had previously been replaced. The failure mileage was approximately 90,000.”

“The oil is low, went to get looked at by another mechanic besides Dealer cause they want to hit you over the head with prices. Was told car burning oil. Took to dealer for Oil Consumption Test. Had to pay for oil change. Came back a little before 1,000 miles and car failed. They charging me 900.00 for next step because I can’t find ALL the oil changes. I just don’t get it, if this is a known issue with this model engine why do I have to pay.”

“On January 26, 2026, my 2019 Hyundai Sonata SEL suddenly became inoperable overnight. The vehicle had been operating normally with no warning signs—no check-engine or oil-pressure light, abnormal engine noise, overheating, loss of power, or other indication of an impending failure. The following morning, the engine would not start. The vehicle was towed to an independent mechanic on January 28, 2026, who determined that the engine was locked/seized. On February 11, 2026, it was towed to Wayne Hyundai for further diagnosis. The vehicle had only 51,533 miles and had received Hyundai’s Knock Sensor Detection System (KSDS) update. Hyundai denied warranty coverage, citing engine sludge, despite my providing a complete service history after resubmiting the missing receipts I had previously misplaced. My primary concern is safety, not the warranty dispute. A sudden engine seizure without warning could cause an unexpected loss of propulsion or create a dangerous situation if the engine fails while the vehicle is being driven. This concerns me because Hyundai Theta II engines have previously been associated with engine seizure and stalling, including issues addressed…”

“The contact owns a 2019 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, smoke started coming from the hood and the vehicle was pulled over into a parking space. While opening the hood, the contact saw that fire was coming from the top of the engine. The contact stated that the fire consumed the front of the vehicle, including the windshield and the dashboard. The smoke coming from the vehicle was dark gray and turned black afterwards. The contact called 911, and the Fire Department was able to extinguish the fire. There were no injuries reported. A vehicle parked next to the vehicle was damaged by the flames. The contact's vehicle was not inspected or officially deemed a total loss. The vehicle was towed to an independent mechanic where an oil change had been performed prior to the failure. The mechanic stated that there might have been a high-pressure fuel valve on top of the engine that possibly caused a gas leak, which started the fire. The vehicle was not diagnosed or repaired. The dealer was not contacted. The manufacturer was not made aware of the failure. The failure mileage was 172,000.”

“The engine is the component or system failed or malfunctioned, and it is available for inspection upon request. Sudden loss of engine power while driving, including during highway speeds or intersections, increasing the risk of a crash. Engine stalling or failure to accelerate, preventing me from safely maneuvering away from hazards. Overheating events, which resulted in complete engine seizure and an unexpected loss of vehicle control, all which can potentially causing catastrophic incident without warning. To include, the increased risk of collision, especially if the failure occurs during traffic, merging, passing, or emergency situations. It has been reported to CC Transmission Auto Repair and independent service center. It was previously inspected by Hyundai dealer. Check engine light present September 2025.”

“For the past several years, this vehicle has experienced a recurring and unresolved engine malfunction that creates a safety hazard. The problem manifests as follows: Symptoms when check engine light illuminates: • Idle RPM elevation to approximately 1500 RPM (normal idle: 800 RPM) • Sudden unintended forward acceleration when foot is removed from brake pedal • Significantly reduced acceleration performance during normal driving • Vehicle becomes difficult to control safely The malfunction occurs intermittently but follows a consistent pattern. This is not an isolated incident but a recurring defect that has persisted for years. Multiple diagnostic and repair attempts have been unsuccessful: • Coconut Creek Hyundai service center - unable to diagnose [DATE(S)] • Independent mechanics - unable to resolve [DATE(S)] • Issue remains unresolved despite multiple service visits Despite multiple attempts by qualified technicians, the root cause has not been identified and the defect has not been corrected. This malfunction creates a significant safety hazard: • Unintended acceleration increases risk of collision • Reduced acceleration capability limits ability to merge…”