2017 Hyundai Sonata Complaints

ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM — Filed 07/11/2026

I am writing to report a direct violation of the Theta II Class Action Settlement terms by Hyundai Motor America. This morning , I emailed an Executive Case Manager explicitly explaining that my 2017 Sonata has an active P1326 code, has the 2019 KSDS update, and requires a mandatory diagnostic under NHTSA Recall 17V226 that cannot be denied due to a salvage title. Instead of replying to my facts, the Case Manager Kathy gave me a hard denial falsely framing my federal recall safety request as a "voluntary goodwill warranty" issue to justify her rejection. Please help me in getting authorization my car with Hyundai dealership in Plano Tx to run the bearing rod test and get it fixed.

UNKNOWN OR OTHER,ENGINE — Filed 06/25/2026

My engine seemed to be consuming oil way to much I had to do a oil change at 61,000 recommend by tire plus but at 58,000 is when I had to change my oil I also noticed there is a buring smell and its also been leaking oil at times I went to get it checked out by a mechanic at tireplus but they also they are seeing that the oil consumption was not normal and they recommend a possible recall for it because it hazardous for how fast its consuming and the leaks

ENGINE — Filed 06/19/2026

Driving home from work on [XXX] (not a safe location)when my car lost power and engine light began to flash. I pulled off to the side of road and called my dad. He came with a code reader and said there was a code P1326. He cleared the code and car drove normally again. 2 days later it began to run rough. I was told about the engine recall so I called Hyundai corporate and told them this same story. I was advised to take to dealership and have the “rod bearings inspected” and shouldn’t matter that my dad cleared the code. The dealership(Massey Hyundai MD) said it had a burnt valve and not part of warranty. But never checked rod bearings. When I called corporate. They said nothing they could do. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ENGINE — Filed 08/29/2025

High oil consumption, burning a quart of oil or more every 500 miles since bought used at Hyundai dealership.

POWER TRAIN,ELECTRICAL SYSTEM,ENGINE — Filed 09/26/2021

My 2017 Hyundai Sonata SE, equipped with the Theta II 2.4L GDI engine, is experiencing severe powertrain failures including rhythmic metallic engine knocking, catastrophic oil consumption, and un-commanded surges/jumping in speed while driving. These symptoms manifested following an unauthorized engine replacement performed by Hyundai of El Cajon under Repair Order [XXX], where the dealer covertly outsourced my vehicle to a third-party shop (Legacy Motor Works) to install an unverified used salvage engine block rather than a certified factory assembly. This vehicle is a Class Vehicle under In re: Hyundai and Kia Engine Litigation (Case No. [XXX]), and the KSDS software update (Campaign 953) was successfully completed on my vehicle in 2019. The engine knock, surging, and oil consumption are consistent with the known connecting rod bearing failure defect described in NHTSA investigation PE17-007. The dealership is currently denying warranty coverage, citing a mileage limit that does not exist under my Lifetime Powertrain Warranty, and they are withholding physical documentation of the repair terms. The vehicle is also experiencing secondary safety failures, including a continuous airbag SRS warning light (two years) and electrical shorts caused by the salvage-yard alternator installation, which have destroyed 4 to 5 car batteries. This engine failure represents a significant safety hazard, as the vehicle periodically loses power and surges without driver input. I am requesting that NHTSA investigate this pattern of warranty denial, parts-sourcing fraud, and the safety risks posed by this substandard engine installation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

STEERING,AIR BAGS — Filed 05/11/2026

The RED light is lit on the dashboard for the airbag. Unable to use steering wheel electronic features which helps with and was designed for hands free controls. I am unable to cycle through the electronic features or engage the cruise control due to the steering wheel electronics are in-op. Please help and get a recall started. This is not on the consumer.

SUSPENSION,POWER TRAIN,ENGINE — Filed 05/27/2026

[XXX] [XXX] [XXX]; [XXX] [XXX] [XXX] Date: XXX To: National Highway Traffic Safety Administration Office of Defects Investigation (ODI) Subject: Formal Safety Defect Complaint – 2017 Hyundai Sonata Theta II Engine Failure, Excessive Oil Consumption, Intake/Engine Component Failure and Safety Hazard Dear Sir or Madam: I am submitting this formal complaint and request for immediate investigation into the dangerous and ongoing mechanical failures involving my 2017 Hyundai Sonata equipped with the Theta II engine. I believe this vehicle contains a serious manufacturing and/or engineering defect that presents a substantial safety hazard to consumers. My vehicle has experienced a pattern of progressive mechanical failure beginning with abnormal and excessive oil consumption, which appears to be directly associated with malfunctioning engine airflow and intake-related components. Specifically, the lower engine airflow system and intake functionality appear defective, placing excessive strain on the intake manifold system and contributing to cascading engine failures. As a result of these failures, the vehicle has experienced: Severe and excessive oil burning/consumption Intake manifold malfunction and abnormal operating stress Suspected overheating and/or premature head gasket failure Ignition coil failure and electrical shorting/misfires Progressive engine deterioration rendering the vehicle unsafe and unreliable Increased risk of sudden engine shutdown, stalling, fire hazard, or catastrophic engine failure while operating The vehicle has become increasingly unreliable and inoperable due to these conditions. These failures raise significant concerns regarding public safety, especially given the known history of complaints and recalls associated with Hyundai Theta II engine defects. I am deeply concerned that this vehicle may reflect a broader pattern of defective manufacturing, insufficient quality control. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM — Filed 04/11/2026

Supplemental Information to Existing NHTSA Complaint involving a 2017 Hyundai Sonata Plug-in Hybrid (VIN: [XXX] ) While traveling at approximately 70 MPH on a heavily traveled highway, the vehicle suddenly and completely lost propulsion without warning. The vehicle rapidly decelerated in traffic, creating a significant safety hazard for my family and surrounding motorists and requiring emergency maneuvering to reach the shoulder. The vehicle was towed to an authorized Hyundai dealership, where diagnostic testing identified multiple high-voltage battery system fault codes: • P0B68 • P0B6D • P0B72 The dealership diagnosed a high-voltage battery system failure requiring battery replacement. The vehicle is currently non-drivable. During my research, I found multiple owner reports involving Hyundai Sonata Hybrid and Plug-in Hybrid vehicles experiencing loss of power, hybrid system failures, limp mode conditions, and propulsion-related incidents. I also learned that Hyundai previously issued Recall 18V166000 involving 2016–2018 Sonata Plug-in Hybrid vehicles due to battery management system and voltage protection device concerns that could result in loss of power while driving. Dealer says does appply for my car. Although my vehicle’s fault codes may differ from those addressed in the recall, both involve battery-related failures capable of affecting propulsion and creating a highway safety risk. My concern extends beyond my individual vehicle. A high-voltage battery or battery management system failure that can cause a complete loss of propulsion at highway speed without warning presents a potentially serious safety risk. I respectfully request that NHTSA evaluate whether similar incidents involving Hyundai Sonata Hybrid and Plug-in Hybrid vehicles indicate a broader safety concern warranting further review. I can provide dealership diagnostic reports, repair estimates, towing records, photos, and videos upon request. Thank you for your consideration, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

UNKNOWN OR OTHER,ENGINE — Filed 05/14/2026

I am writing to report a serious, premature failure of a primary emissions and safety-related component (the catalytic converter) that has occurred as a direct consequence of a known, unaddressed manufacturing defect in Hyundai's Theta II engine. My vehicle has a documented history of excessive engine oil consumption. This inherent manufacturing flaw causes the engine to burn motor oil at an extreme rate, forcing unburned oil directly into the exhaust system. Over time, this oil has fouled and destroyed the catalytic converter substrate, triggering trouble code P0420 and causing a complete component failure. A dealership inspection at Heritage Hyundai Towson (RO #XXX) confirmed "excessive wear" and failure of the catalytic converter. Because the catalytic converter is failing prematurely due to a liquid defect (excessive oil burning) rather than standard wear and tear, it poses an environmental hazard, compromises vehicle emissions control, and can lead to sudden engine stalling or reduced power while driving, presenting an active safety risk. Hyundai Motor America (Case #XXX) has formally denied assistance to rectify this consequential damage, despite full awareness of the underlying engine defect. I request that NHTSA investigate how Hyundai’s ongoing oil consumption manufacturing issues are causing cascading safety and emissions component failures in these vehicles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ENGINE — Filed 04/27/2026

The rod bearings failed in the engine. The vehicle is currently at the dealership and is available for inspection. Rod bearing failure can cause complete engine seizure while driving, creating a serious risk of losing vehicle control at any speed. This is a known issue with Hyundai's Theta II engine. Yes. The dealership performed a diagnostic on April 27, 2025 and confirmed rod bearing failure. Yes. The dealership inspected the vehicle and Hyundai corporate opened a warranty case and arranged the repair appointment, initially confirming coverage before later denying the claim without providing documentation. The dealership has also repeatedly failed to provide documentation supporting the denial of my warranty claim despite my requests beginning April 29, 2025. I have also been unable to get callbacks from the dealership after being promised updates on May 1st, May 7th, and after requesting a manager on May 18th. As of May 27, 2025 I have still not received any documentation or a callback. The check engine light came on prior to the failure. I proactively checked and changed the oil, added Lucas oil treatment, replaced the spark plugs, and replaced the battery attempting to diagnose and resolve the issue before bringing it to the dealership. No oil pressure warning light ever appeared. The check engine light persisted despite these efforts which is what led me to bring the vehicle in.