This vehicle has experienced multiple hybrid system failures while driving, including a complete loss of power -??Hybrid System Warning -?" Turn Engine Off-?? on the interstate in June 2022 through November 2025. These events have placed me and my loved ones in dangerous driving situations. Despite a warranty-?'covered engine replacement at 82,015 miles (January 2023), the same hybrid system issues have recurred. Hyundai initially indicated a warranty claim was submitted, then told me there was no record of any claim in the system. The dealership claims it was denied -?" creating a serious inconsistency in communication and accountability. In addition, I have identified multiple NHTSA complaints in the database from other owners of 2016 Sonata Hybrids (VINs beginning with KMHE) describing similar highway shutdowns and hybrid system failures, which raise concern about a broader, unaddressed safety defect not currently covered by existing TSB or recall actions. I am respectfully requesting: A regional inspection and review of my vehicle prior to any further work. A review of Hyundai-??s handling of this warranty claim and the discrepancy between dealer and corporate communication. Assessment of whether the hybrid system failures in KMHE-?'prefix Sonata Hybrids warrant further safety action.

- Maywood, IL, USA

I am filing a complaint against Hyundai Motor America regarding denial of defect coverage for my 2016 Hyundai Sonata (VIN: [XXX] ). The vehicle is experiencing excessive oil consumption and triggered diagnostic code P1326. The dealer confirmed only one quart of oil remained in the engine and noted a valve cover gasket leak. Hyundai-??s Tech Line instructed a gasket replacement and oil consumption test, but Hyundai corporate formally declined coverage, citing mileage and second-owner status. This is not a routine warranty claim but a defect claim. Oil consumption defects in Hyundai Theta engines are well-documented and have been subject to recalls, Technical Service Bulletins, and class actions. Defect coverage should not be limited to first owners. I am requesting reimbursement for the valve cover gasket repair, acknowledgment of the oil consumption defect, and corrective action to ensure Hyundai honors defect-related coverage fairly. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Lutz, FL, USA

My 2016 Hyundai Sonata experienced a sudden engine failure while in operation with no prior warning lights or symptoms. The engine seized unexpectedly, creating a safety risk. This failure appears consistent with known engine defects affecting Hyundai Sonata vehicles of this model year. Hyundai Motor America denied my claim without addressing these known defect patterns.

- Williamsburg, VA, USA

Vehicle stalled while driving

- Sterling , VA, USA

On November 10, 2025, my 2016 Hyundai Sonata Hybrid (VIN [XXX], approximately 150,000 miles) experienced a sudden loss of power while I was turning right and accelerating into traffic. The vehicle immediately entered limp mode with flashing warning lights and audible alerts. The vehicle lost normal propulsion and could not accelerate properly, creating a dangerous situation as it was blocking a traffic lane. I was forced to limp the vehicle into a nearby parking lot to get out of traffic. The vehicle was not safely drivable afterward and was towed home. A few days later, the vehicle was towed to Murdoch Hyundai in Lindon, Utah, for diagnosis. The vehicle was found to have diagnostic trouble code P1326, which Hyundai identifies as activation of the Knock Sensor Detection System (KSDS) related to connecting-rod bearing wear. This condition is part of Hyundai-??s known engine defect and safety recall/warranty extension programs. During inspection, the dealer observed that the valvetrain did not show signs of neglect or sludge, which is inconsistent with oil starvation or severe maintenance neglect. This further supports that the failure is consistent with the known connecting-rod bearing defect addressed by Hyundai-??s KSDS safety recall, rather than a maintenance-related issue. This is a safety issue because sudden loss of propulsion or reduced power while entering traffic creates a high risk of collision. Hyundai customer care has been unwilling to open a new case number or escalate review, and the dealer has indicated possible denial of engine replacement coverage based on incomplete oil-change records, despite the vehicle exhibiting the KSDS safety condition. I am requesting NHTSA review of this safety-related defect and the manufacturer-??s handling of KSDS/P1326 failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Spanish Fork, UT, USA

My Hyundai is experiencing severe and continuous engine oil consumption that creates a safety risk. The vehicle loses a significant amount of oil within 1,000-?"1,500 miles, sometimes showing almost no oil on the dipstick despite recent oil changes. There are no external leaks, no burning smell, and no visible oil under the car. The cause remains UNKNOWN, but it appears to be internal engine burning or a manufacturing defect. I have taken the vehicle to the Hyundai dealer multiple times. They performed oil consumption tests but either reported -??normal results-?? or did not provide clear explanations. The issue continues exactly the same. I also contacted Hyundai corporate, but no meaningful assistance or goodwill support was provided. The dealer acknowledges no leaks but still refuses to repair or replace the engine. This problem is dangerous because the oil level drops without warning lights or error codes. If I do not manually check the dipstick, the engine could run dry and seize while driving. Sudden engine failure on highways or in traffic can cause accidents. I now have to frequently top up oil just to keep the engine alive. I have maintained the vehicle properly and completed all requested tests. The cause is still UNKNOWN, but based on similar Hyundai cases, it may involve piston rings, valve seals, or internal engine wear. Many Hyundai owners report the same issue, suggesting a broader defect. The dealer-??s only advice is to -??keep monitoring oil, -?? which is not a safe long-term solution. This defect poses a serious safety concern and financial burden. I am filing this complaint so NHTSA can investigate, as the engine may fail unexpectedly, putting me and others at risk.

- Plainfield, IL, USA

My 2016 Hyundai Sonata with the DOHC GDI Theta-II engine is experiencing severe engine oil consumption consistent with Hyundai's known TXXI/TXXC extended warranty defect. The oil pressure warning has flashed while driving or braking, the engine runs rough when slowing down, engine has made knocking noises, and there is smoke/vapor with a burnt oil smell when removing the oil cap after driving. The oil level drops rapidly between changes despite proper maintenance. This issue poses a risk of engine failure, stalling, or fire while driving. I have maintained the vehicle on time with all oil change receipts. A Hyundai dealership refused to perform the required warranty diagnostics even though this issue falls under Hyundai's extended warranty for Theta-II engines. This is a serious safety concern, and no corrective action has been taken.

- Smyrna, GA, USA

Car has been consuming oil fast since around 75,000 miles. Car is under 100,000 miles and I have been told by an independent shop that it basically has piston ring failure which means engine failure.

- Dunn, NC, USA

The vehicle is going through oil very quicky. No leaks no burning.

- Denver, CO, USA

This car burned oil like crazy from the start. We kept the oil changed regularly, had to change spark plugs weekly and add a quart or more of oil each week in between oil changes. One day whole stopped at a red light the engine started knocking for no reason. Once diagnosed it turned out that it had spun a rod bearing. These engines need to be recalled before someone ends up in a fatal accident. This car was driven daily on a major interstate thankfully the issue happened at a red light, but has left me with a car note and a non drivable car. What-??s it gonna take to get these engines recalled and replaced?

- Jackson, GA, USA

My 2016 Hyundai Sonata (VIN: [XXX] ) had its engine replaced under recall campaign 20V746000 in March / April 2024 at Hyundai of Round Rock, TX. In October 2025, less than 18 months later and at 97,000 miles, the replacement engine failed again. Hyundai has refused further repair, citing an expired recall warranty. This raises serious safety and reliability concerns, as a recall engine should not fail this soon. Engine failure while driving could result in a stall or crash risk. Please investigate whether Hyundai-??s recall replacement engines are defective and if extended coverage is warranted for affected consumers. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Georgetown, TX, USA

The vehicle experienced an engine and power train failure while driving on the highway, resulting in sudden loss of power. The electrical system also failed after the dealer visit, causing the battery to die every morning. Yes, the vehicle is available for inspection upon request. My car suddenly lost power on the highway and would not accelerate, forcing me to pull over on the shoulder with traffic moving around me. This created a serious risk of a rear-end collision or crash. Additionally, after the dealer visit, the electrical system began failing and the vehicle has been completely dead every morning, leaving me stranded with a child and unable to reliably start the car. The problem has not been reproduced because the check engine code cleared itself after the incident; however, the symptoms absolutely remain. The dealer refused to diagnose the loss-of-power event because the code was cleared, and they returned the vehicle to me with a dead battery. The electrical issue (car dying every morning) has been happening consistently since the dealer visit. The vehicle was taken to a Hyundai dealership immediately after the incident, but they refused to diagnose the loss of power due to the code being cleared. A mobile mechanic scanned the code at my home before the tow, but the code disappeared afterward. The electrical failure began after the dealer visit and has not been properly inspected by Hyundai. Yes. While driving on the highway, the check engine light came on and the car immediately lost power and would not accelerate. After the dealer visit, the car has been completely dead every morning and requires a jump to start. These symptoms began on the same day as the highway incident and continued after Hyundai serviced the vehicle.

- Bridgeport , OH, USA

Engine issue - but no recalls there have been hundreds of this same car yr and model with engine issues out of the blue

- Bunn, NC, USA

Sudden engine failure. Compression issue, car has only 63,000 miles.

- Rogersville, TN, USA

While driving, my 2016 Hyundai Sonata-??s engine suddenly started knocking loudly. I stopped immediately and found the engine oil was very low without any prior warning. After adding oil, the engine still runs but with possible internal damage. This could have caused the engine to seize while driving. There were no warning lights or leaks before this happened.

- New Castle, DE, USA

High engine oil consumption 2 qts every 1k miles.

- Malden , MA, USA

Car had oil in the electrode of spark plug. Total engine failure

- Crestwood, KY, USA

The problem with my vehicle is a failure of internal engine components, specifically a known defect in the piston rings of the Hyundai Theta II engine. This failure causes excessive oil consumption, which is burned internally. The internal engine components have failed, leading to a widely documented defect in the Hyundai Theta II engine. The primary symptom, which began to get serious around 80,000 miles, is the constant need to add oil to the engine every two weeks. If I do not do this, the low oil warning light illuminates on the dashboard, serving as a continuous alert of the problem. This failure was officially confirmed by an authorized Hyundai dealership. About two weeks ago, they first documented that there were no external leaks on the vehicle. When I returned because the oil had been consumed again, they performed a new diagnostic, for which I paid over $300, that confirmed the engine is burning oil internally. The dealership, acting as the manufacturer's representative, is the only entity that has formally inspected the vehicle. The situation places my safety and the safety of others at serious risk. First, the oil consumption can lead to a sudden and catastrophic engine failure, resulting in a loss of power and control of the vehicle while in transit. More alarmingly, the guidance I received from Hyundai staff was to simply "wait for the engine to stop working or start making a lot of noise." As someone who depends on the car for a daily commute, following this dangerous recommendation is an unacceptable risk.

- Fort Lauderdale, FL, USA

At 70712 miles cylinder 4 suffered a catastrophic internal failure. The vehicle also had excessive oil consumption and the dealer just told us to keep adding oil as there was nothing they could do. The vehicle must have had a manufacturing defect.

- Hayden, ID, USA

Was driving on the interstate, and took the exit I needed. Upon exiting before coming up to stop light, noticed check engine light flashing, and couldn't accelerate. RPMS were bouncing when I tried to accelerate. Pulled off onto side of road, called mechanically inclined friend who came with an obd2 sensor, and it was showing a P132600 code for Knock signal range performance, with an audible knocking sound, and engine vibration while on in idle. Got the code cleared so we could drive the car the 3 miles I needed to go to get to where I was going, 2 miles in, the engine light came back on and vehicle went back into limp mode. Called AAA and got the car to an in network mechanic shop for Carvana, whom i bought the car through a month prior. Proceeded to do an oil sample test and found it to be full of metal shavings. Said engine would need to be fully replaced. Vehicle is currently still at mechanic until SilverRock gets the claim and will see if the engine replacement is covered under warranty. Certified Automotive Inc. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Wilmington, DE, USA