Hyundai Sonata loss of power problems

Filed Nov 9, 2026 · Engine · TX

was driving my 2015 Hyundai sonata with my daughter and there was a really loud thump, like something came apart. there was instant smoke and really loud knocking and reduced power. Right after that, I pulled over into a church so I wasn't blocking traffic, and when I got out, there was oil coming out everywhere and a hole in the engine block. I read about a lawsuit settlement and seeing that alot of drivers get a flashing engine light and car reduce power. That is not what happened with me, was just a loud pop, smoke and loud knocking. This has put me and my daughter at risk. I’m asking the federal safety agency to investigate why an engine with an update that was installed to prevent what happened could fail on the road, produce that much smoke, and spill oil the way it did. I had a driveway to pull into but another driver might not of have nowhere safe to go. If Hyundai knew this type of failure could happen, I want the federal safety agency to look at whether the update gives drivers enough warning and whether more needs to be done to keep these cars safe on the road.

Filed Oct 27, 2026 · Engine · NY

On August 19, 2026, at 76,170 miles, the engine in a 2012 Hyundai Sonata GLS suddenly lost power and shut off while the vehicle was moving on gas station property. The driver had traveled approximately 10 feet before the engine stopped. Repeated attempts to restart were unsuccessful; the engine would not crank. The driver shifted into neutral and pushed the vehicle to a safe location. Before the failure, the vehicle was running smoothly, with no warning lights, warning messages, unusual noises, or other symptoms. There was no collision, injury, smoke, or fire. The sudden, unannounced loss of propulsion created a safety concern because the vehicle could no longer move under its own power. Fortunately, the driver was still on the gas station property and was not blocking traffic. An independent repair shop inspected the vehicle and confirmed that the engine was mechanically locked up. The vehicle was subsequently taken to an authorized Hyundai dealership for inspection. The dealership’s service adviser reported lower rod-bearing failure. Hyundai later denied engine-replacement coverage, citing neglect and missing maintenance records. That denial is being disputed through BBB arbitration. The vehicle had received an oil and filter change and a mechanical inspection on August 4, 2026, at 74,548 miles—15 days and 1,622 miles before the failure. The vehicle remains at the Hyundai dealership, and the engine is available for inspection upon request. The exact underlying cause of the reported bearing failure is UNKNOWN.

Filed Oct 14, 2026 · Engine, Fuel system · MS

A franchise dealership performed a federally mandated safety recall service (ECM Software Update) and a knock sensor replacement on this 2015 Hyundai Sonata 2.0L Turbo. To perform these specific repairs, the technician had to work directly around the intake and turbocharger assembly workspace. Immediately after picking up the vehicle, it suffered a sudden and dangerous loss of power and refused to accelerate normally on the highway, creating a severe traffic hazard. Upon an immediate emergency inspection by the same service center 5 days later, the dealership documented in writing that the turbocharger intercooler hose clamps were completely off/unfastened. Because the technician left the clamps disconnected, the turbo lost sealed pressure, failed completely, and began dumping high-pressure engine oil backward through the air filter intake box. The service center is now refusing to take responsibility for the mechanical safety failure directly caused by their technician's recall repair negligence.

Filed Oct 7, 2026 · Engine · NY

2013 Sonata 2.4 81,953 mi, seized on highway with fresh oil change 1 week prior, loss of power, steering/braking. Happened on George Washington Bridge (NY/NJ) with near collision. Asssited by Police to move vehicle out of highway. Inspected by dealer (Paramus Hyundai) and confirmed loss of power due to engine problem. Dealer denied warranty for poor maintenance despite receipt showing recent maintenance. This vehicle is covered under life warranty by Hyundai for manufacture defective engine, yet they denying engine replacement. The engine problem is a serious safety risk.

Filed Sep 28, 2026 · Engine · FL

Factual summary * Vehicle: 2013 Hyundai Sonata * VIN: [XXX] * Incident date: XXX * Failure: Sudden knocking noise, immediate check‑engine illumination, loss of power, and catastrophic engine failure; vehicle towed to Allen Turner Hyundai, 6501 Pensacola Blvd, Pensacola, FL 32505. * Recall: My VIN appears on Hyundai’s engine recall list; the recall notice was issued before the vehicle received a rebranded title. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 23, 2026 · Brakes, Driver assistance · NY

While driving at highway speeds, the emergency brake system will apply and alert me. It’s happened twice now in the last 3 weeks. I’ve experienced a random loss of power while driving on the highway with no check engine light on the dashboard. Lastly, at lower speeds the car will randomly jerk while accelerating with no lights on the dashboard as well. I’ve gone to the dealership but they wanted to charge me a diagnostics fee to first look over the vehicle, which I don’t feel I should be on the hook for since the issue isn’t user caused.

Filed Sep 15, 2026 · Engine · TX

The vehicle experienced a Theta II engine failure at under 57,830 miles while driving on northbound [XXX] near the [XXX] Parkway U-turn in [XXX]. The engine made a loud noise and lost power. I was able to coast to the far right side of the U-turn under the bridge. I called HERO (Austin's emergency roadside assistance). They responded, determined it was not a battery issue, and pushed the vehicle to the Southern Leisure Spa parking lot on the southbound side of the road. The vehicle was then towed. The vehicle is equipped with the KSDS (Knock Sensor Detection System) software update, installed as part of Hyundai's remedy for this known defect. Despite KSDS being installed, the engine failed due to connecting rod bearing wear, consistent with the documented Theta II defect. A Hyundai dealership confirmed KSDS was installed but denied the warranty claim, citing maintenance records. The vehicle is available for inspection upon request. The Theta II engine defect has been the subject of prior the federal safety agency investigations and Hyundai recalls. This complaint is filed to document another failure of the same defect in a vehicle with the manufacturer's remedy installed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 8, 2026 · Engine · NC

On September 8, 2026, while driving a 2013 Hyundai Sonata Limited at highway speed, the check-engine light began flashing and the vehicle suddenly lost power. The vehicle slowed to approximately 40 mph, then approximately 20 mph, before the engine completely shut off. I had to maneuver the vehicle to the side of the highway while surrounding traffic continued traveling at highway speeds. This created a serious risk of a rear-end collision or other accident. The engine would not operate afterward and appears to have seized. The vehicle had approximately 100,000 miles at the time of the incident. There had been no clear warning of an imminent engine failure before the check-engine light began flashing and the vehicle lost power. The vehicle has not yet received a complete diagnostic inspection, so the precise cause of the failure is currently unknown. The vehicle is available for inspection upon request. No crash, fire, or injuries occurred, but the sudden and severe loss of power created an immediate safety hazard.

Filed Sep 3, 2026 · Engine · 52,973 miles · FL

The contact owns a 2013 Hyundai Sonata. The contact stated that while driving 40 MPH, the vehicle suddenly lost power. The contact was able to coast to the side of the road and turned off the vehicle. The vehicle was unable to restart on the side of the road. The vehicle was towed to a certified mechanic who diagnosed that the engine had seized and needed to be replaced. The vehicle was then towed to the dealer, who confirmed the diagnosis. The dealer asked the contact to provide receipts of past oil changes. After submitting the information to the manufacturer, the request to cover the repair was denied. The vehicle remained with the dealer for a month. The manufacturer was informed of the failure by the dealer. The failure mileage was 52,973.

Filed Aug 25, 2026 · Engine · WA

Component & Inspection: Vehicle engine suffered connecting rod bearing failure and entered restricted P1326 "Limp Home Mode" (max 2,000 RPM). The vehicle is grounded and available for inspection at Bud Clary Hyundai in [XXX].Safety Risk: Sudden, unexpected loss of power occurred while driving, placing me and other drivers at immediate risk on public roads due to the vehicle's inability to maintain normal traffic speed or safely accelerate.Dealer & Corporate Confirmation: Active P1326 engine code is confirmed. Car has been held for 14 days. The franchise is violating federal settlement rules by explicitly refusing to execute the mandatory, free mechanical Bearing Clearance Test (BCT) unless I pay out-of-pocket fees.Inspection & Corporate Compliance Failure: Car was brought to the dealer on XXX. The service manager admitted in writing that they are withholding safety diagnostics to protect shop labor hours due to an automated computer flag regarding a clerical title brand discrepancy. Hyundai Corporate is actively enabling this violation; my case manager refuses to issue a manual compliance override for the safety test and is violating federal settlement terms by withholding my contractually mandated alternative transportation.Warning Lamps & Symptoms: Flashing Check Engine Light and limp home mode triggered instantly and unexpectedly on XXX. There were zero warning symptoms, messages, or abnormal noises prior to that date INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)