2023 Hyundai Sonata

I own a 2023 Hyundai Sonata SEL. Over approximately three years, the vehicle experienced four separate incidents involving sudden loss of engine power and recurring fuel injector/powertrain problems. Three of these incidents occurred while the vehicle was being driven on interstate highways, creating serious safety concerns. The first incident occurred on XXX, on [XXX] [XXX]. My daughter was driving the vehicle at the time when it suddenly lost power while traveling on the interstate. She had to maneuver the vehicle to the shoulder under unsafe traffic conditions. The second incident occurred on XXX, on [XXX] near [XXX]. I was driving the vehicle when it again experienced sudden loss of power while traveling at highway speed. The third incident occurred on XXX, in [XXX]. The vehicle experienced another significant power-loss event and required roadside assistance. The fourth incident occurred on XXX, on [XXX]. The vehicle again experienced a sudden loss of engine power while I was driving on the highway. Despite multiple repair attempts, including repairs related to the fuel injectors, the same or substantially similar power-loss problem continued to recur. Because the vehicle has repeatedly lost engine power while being driven, including multiple incidents at interstate highway speeds, I believe this recurring condition presents a serious safety risk. I am reporting these incidents so NHTSA can evaluate whether this may represent a broader safety-related defect affecting this vehicle model. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11755422

Incident

Jun 30, 2026

The contact owns a 2023 Hyundai Sonata. The contact stated that while driving approximately 15-40 MPH, the vehicle was sputtering and shaking abnormally. The failure was a recurring failure. The contact associated the failure with NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); but the VIN was not under recall. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 86,500.

NHTSA ID

11753540

Incident

Jul 16, 2026

Mileage

86,500 mi

The contact owns a 2023 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the transmission shifted into neutral(N) and failed to shift into park or drive on three occasions. The vehicle was restarted. After restarting the vehicle, the vehicle was shifted into drive, and the contact continued driving. The message that the vehicle could not be shifted into other gears was displayed. The vehicle was originally purchased in another state. The vehicle was taken to the local dealer to be diagnosed. The dealer determined that the battery and fuel injector pump needed to be replaced. The vehicle was repaired; however, the failure recurred. The manufacturer was not contacted regarding the failure. The failure mileage was approximately 50.

NHTSA ID

11744098

Incident

Jun 13, 2026

Mileage

50 mi

This is an extremely common issue plaguing Hyundai & Kia vehicles with the Theta III 2.5L Turbo engine, Such as Kia K5 GT, Hyundai Sante Fe, Hyundai Santa Cruz, & Hyundai Sonata N-Line. Its a failing ITM (integrated thermal management) unit or otherwise known as an ITMS unit. There is a rod within the ITM that prevents proper control of the flow of cooling the oil and engine coolant of the engine. Results in Cooling issues, such as a cold lower radiator hose while the engine is hot, or 'limp mode' during acceleration, that causes a sudden loss of power while trying to merge on the expressway. There has been other Kia models and years that have had TSB's related to fixing this issue, but Hyundai has released nothing. I have uploaded an example of one of the TSB's that do not apply to my car. Technical symptoms often include: Fans running 100% full duty (high) while the lower radiator hose stays cool. Or Fuel dilution or a 'rich' running engine. Because the engine is overcooling that keeps the car's fueling rich and in a open loop mode affecting emissions and contaminating oil. Personal Details of exactly what happened when i noticed mine was failing. I ran home on my lunch break, and while accelerating on a ramp to get up on a highway, my car started beeping and flashing "Engine Overheated" and i immediately let off the gas with preparation to pull over. The second i left off the gas, the coolant temp within 1-2 seconds went from a little over 3/4 the way up the gauge back to normal a little below half temp. I resumed driving a 3 mile drive back to work, with it showing normal temps the rest of the way. I popped the hood when i got to work to see if coolant was low, and it was completely normal, a little over halfway between the min/max lines. The car continues to run hot, often with the cooling fans running at 100%.

NHTSA ID

11737860

Incident

Feb 25, 2026

Was driving and stopped at a stoplight. When I went to drive it started sputtering and if I wouldn’t have driven into a gas station, it would’ve given out in the middle of the road. It wouldn’t let me switch to drive or reverse , only neutral or park. It threw a code P0301, cylinder 1 misfire. Had to get it towed. Now I have to get my spark plugs and fuel injectors replaced.

NHTSA ID

11737351

Incident

May 5, 2026

The contact owns a 2023 Hyundai Sonata. The contact stated that while his wife was driving at an undisclosed speed, the message "Engine Overheated" displayed. The contact checked the Hyundai app, but it showed no failure. The contact's wife drove to their son's residence, who inspected and discovered that there was no coolant in the engine. The contact's son added coolant to the engine. The vehicle was taken to the dealer, who replaced the coolant valve, exhaust muffler assembly center, clamp assembly exhaust pipe, two gasket exhaust pipes, and added coolant. The contact related the failure to Technical Service Bulletin: 23-EM-009H (EHRS Coolant Leak Repair); however, the vehicle was not covered under the TSB. The manufacturer was made aware of the failure, and a case was filed. The failure mileage was approximately 18,500.

NHTSA ID

11737251

Incident

Apr 17, 2026

Mileage

18,500 mi

See attached document for complaint.

NHTSA ID

11728741

Incident

Feb 25, 2026

Battery Management System completely exhausting the 12V battery resulting in the car acting as if it has no power. When this happens, you can't unlock the door or open the trunk. On two separate occasions, I have encountered a complete loss of power in my Sonata Hybrid, preventing me from unlocking the trunk or doors upon returning from extended trips. The first incident occurred after a ten-day absence last Fall, and the most recent was on Saturday, March 14, 2025. During the latest incident, I returned from a seven-day trip and found my vehicle parked at Orlando International Airport. Upon approaching the car, I anticipated being able to unlock the trunk, load my luggage, enter the vehicle, and drive home. However, once again, the vehicle was unresponsive. Accessing the car required removing the cap from the door handle and manually inserting the key, a process that took approximately ten minutes, which was particularly inconvenient and concerning in an airport parking lot. This situation was even more challenging considering I am a [XXX] woman of smaller stature attempting to resolve this issue alone at night. I believe this poses a serious safety concern for all owners under similar circumstances. Following the incident last Fall, I brought my Sonata Hybrid to Key Hyundai in Jacksonville. I was informed that this is a known issue for which there is a recall; however, my vehicle model year is not included in the affected range. It was suggested that I would need to manage this problem independently. I believe this recurring issue represents a known vulnerability that could potentially expose Hyundai and its dealerships to liability should an owner suffer harm while addressing this malfunction. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11724724

Incident

Mar 14, 2025

This bulletin provides information related to a Transmission Control Unit (TCU) software update for some vehicles equipped with an 8-speed wet dual clutch transmission (8WDCT). The software update revises the touch point learning variation, improving drivability and judder symptoms. Some 8WDCTs (indicated by a new part number) received an updated clutch spring. The correct TCU software update must be matched with the correct corresponding 8WDCT hardware, otherwise, drivability concerns may occur. This service procedure should be performed prior to any 8WDCT replacements done for drivability/judder concerns.

This bulletin provides information related to the navigation and head unit software changes introduced in the 2026 1st Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system. Refer to the 2026 1st Navigation Map and Software Update Key Improvements and Additional Improvements tables in this TSB for a list of specific changes. The software can be downloaded via Navigation Updater (NAU) and updated by USB.

Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter magnetic switch for potential freezing and, if necessary, replace the starter magnetic switch (solenoid) assembly.

The National Highway Traffic Safety Administration (NHTSA) has identified the presence of substandard and dangerous driver’s-side airbag inflators manufactured by Jilin Province Detiannuo Automobile Safety System Co., Ltd. (DTN). These inflators were not supplied, approved, or authorized by the vehicle manufacturers and have primarily been found in vehicles that previously experienced a crash and underwent airbag replacement using non-genuine parts. These dangerous inflators have ruptured during deployment, posing a serious risk of injury or death due to metal fragments entering the vehicle cabin. To date, Hyundai is aware of three people who have died while driving a Hyundai vehicle with one of these substandard replacement airbag inflators that deployed in what likely would have been a survivable crash. NHTSA has issued a public advisory urging vehicle owners and service professionals to have vehicles inspected if there is reason to believe that a non-genuine replacement airbag may have been installed. Vehicles with salvage or rebuilt titles, prior airbag deployments, or unknown repair histories may present a higher risk. NHTSA strongly cautions against self-inspection by vehicle owners and recommends inspection by trained technicians.

The National Highway Traffic Safety Administration (NHTSA) has issued an urgent safety advisory regarding dangerous, counterfeit driver‑side airbag inflators manufactured by Jilin Province Detiannuo Automobile Safety System Co., Ltd. (DTN), that have been identified in U.S. vehicles following prior crashes, theft, or non‑certified airbag replacements. These inflators are not approved for use, may rupture during deployment, and have caused serious injuries and fatalities. Please see attached announcement, provided by NHTSA, for more details.

Some 2019MY and newer vehicles equipped with a front view camera may illuminate certain warning lights and trigger DTC C272246 fault code for the front camera. In the following cases, the front camera auto-calibration range may be exceeded while driving: • If the front camera is not properly installed and is completely or partially detached. • In case of excessive changes affecting the vehicle's balance (e.g., loading excessively heavy cargo in a specific location of the vehicle, or significant under-inflation of the tires). • Specific road conditions affecting the vehicle's balance (e.g., excessive road crown) This TSB provides instructions on how to service the vehicle when the front camera related warning light(s) are triggered due to system out of calibration (DTC_C272246).