61 of the
1,162 complaints filed about the Hyundai Sonata Hybrid
are about the fuel system —
5% of everything owners reported.
The worst model year for it is 2013.
The primary failure is in the Engine/Powertrain system and Knock Sensor Detection System (KSDS), causing 6 identical sudden engine stalls (OBD-II code P1326) from 09/2000 to 06/2026. Additionally, severe excessive oil consumption was documented during 2 of these diagnostic visits, showing deep-seated engine issues. The vehicle and all records are available for inspection at the Hyundai dealer. Safety was severely threatened on 6 occasions. The vehicle abruptly stalled at 60+ mph in active highway traffic, forcing an immediate engine shutdown. This left me with highly impaired steering and braking control in fast-moving traffic, creating an imminent risk of high-speed rear-end collisions and jeopardizing my life and others. The primary stalling defect and P1326 code were confirmed 6 separate times by the authorized Hyundai dealership. The secondary excessive oil consumption issue was also formally confirmed by the dealer during 2 of those visits. Despite multiple dealership-confirmed diagnoses, no permanent repair has been achieved. The vehicle has been inspected during all 6 visits by dealership technicians. For the current (6th) visit, the dealer could not resolve the recurring defect and formally contacted Hyundai Corporate Technical Support for expert analysis, which is currently ongoing. Except for the first visit, the pattern is identical: the car stalls, the dealer clears codes/replaces KSDS, and it stalls again within 3 weeks. Notably, during the 4th visit, they replaced the Intake Manifold. Now, on this 6th visit, they demand I pay to replace that same part again. This proves they cannot diagnose the root engine failure and are only applying useless, temporary fixes. Prior to all 6 stalls, the flashing Check Engine / Hybrid Warning light triggered on the dashboard. This critical KSDS alert was followed within seconds by a total loss of motive power. Also, a history of rapid engine oil depletion and low-oil alerts was documented in 2 of the diagnostics.
NHTSA complaint #11750679 — an unverified report by a vehicle owner.
UNKNOWN- While driving on highway, from 70 mph speed the car suddenly lost acceleration and speed dropped. No response to accelerator. Even with pushing the accelerator high, car will go in high RPM and speed will barely reach 40 mph. I was lucky that there was no other vehicle behind me, especially heavy automobile like semi truck as it would have crashed in me from behind due to sudden propulsion loss. The car started working fine next day. I took it to dealer and they couldn't find any error code but said it could be 12V battery BMS software update and they updated it. They mentioned that this is NOT a safety issue which is mind-blowing and concerning as this is a MAJOR safety hazard. I would request you to investigate this further and if this is a software issue then please direct Hyundai to update this with all vehicles and cover the cost for those who have had to pay for it.
NHTSA complaint #11704561 — an unverified report by a vehicle owner.
On 11/28/25 at approximately 6:30 pm, I was driving on a Highway 17 going about 60 mph when my car's engine completely shut down. a "Hybrid System Failure" warning flashed and my car was no longer drivable. The car was towed to the dealership. In mid October 2025, my car stopped running with the same "Hybrid System Failure" warning, but it happened in my driveway. The car was towed to the dealership and supposedly repaired.
NHTSA complaint #11702405 — an unverified report by a vehicle owner.
The car will randomly lose acceleration and jerk forward. It will make a beeping noise while the hev system warning flashes on the dash. It also says to turn off engine. While the warning is flashing and engine light is on it goes into a limp mode and you have limited acceleration. It has almost caused multiple wrecks when I go to acceleration from turning or at lights in traffic because I cant go over 20-30 mph. I have turned the car on and off and the hev system and engine light turns off and the car continues to work normal. It eventually comes back on and does the same loss of power/hev warning. It will be random and does not matter on how fast you are going to trigger the warning lights and loss of power.
NHTSA complaint #11692279 — an unverified report by a vehicle owner.
Fuel injector failed. The vehicle stall and accelerate poorly due to misfires. It is leaching gasoline into the oil which can result in total engine failure. Dealership verified the injector was bad. There was a warning light at one time after refueling, presumed it was my fuel cap, tightened it, and the light went away.
NHTSA complaint #11685272 — an unverified report by a vehicle owner.
The vehicle went in for repair at the dealership early July for a check engine light and DTC error code. It was revving high after being driven for more than 20 min or so and wouldn’t get to above 60 mph. Jerky, dangerous acceleration and deceleration seemingly out of nowhere. The dealership replaced the fuel pump which is what they said was causing the error. Today on August 10th, check engine light popped up again with a DTC error code. Weird acceleration and deceleration and general jerkiness when driving. Scheduled service appointment for next week.
NHTSA complaint #11679707 — an unverified report by a vehicle owner.
Purchased 2019 after 44,000 miles engine was replaced metal in engine and inverter coolant issue July 2025 117,000 my inverter coolant light came in and off several times then car through all warning lights hev check engine warning shut it down went into limp mode Towed to dealership they checked and cleared codes said it threw 13 codes but after clearing they stated nothing wrong with it As they went to pull car around it happened again this time code was knock sensor which they relaxed at no charge extended warranty They next day after picking up while at idle hev warning went in shut car off and it was gone kept driving nonissues The next day again it happened and this time the engine light stayed on Spoke with dealership they said they would charge me diagnosis charge of 208 and if it was related to what they did. It would be covered also stated if the engine light was flashing it would be covered or it isn’t the engine isn’t covered The inverter coolant is not bubbling or moving when car is on it is an inverter coolant issue that was a problem back when my first engine was repaired and should be covered I love my vehicle but I have had so many issues since getting it major things and the lighting system showing a black spot in my view as well that could not be fixed I will attach pictures of earning lights and video of coolant not circulating and the dealership filled the coolant way over the top I have to now take it back again to have it looked at
NHTSA complaint #11674772 — an unverified report by a vehicle owner.
Car is a Sonata Hybrid Limited equipped with a solar roof which charges the hybrid battery. Vehicle began to cut off battery power while parked, requiring the use of a factory equipped 12V override switch in March 2025 after approximately 3.5 years of ownership. This occurred multiple times, often when the car was parked in the sun but independent of how long it had been driven prior or how long it had sat without being started. Evaluated by two Hyundai dealers; second dealer found a fault in the "solar DCDC converter" as well as the hybrid battery bulging. Battery module replaced. Unclear if this resolves the issue or it will recur again. Am speaking to Hyundai regarding battery warranty extension as vehicle had 88000 miles on it at the time of the issue starting. Online fora (e.g., Reddit, Facebook) note other customers who have had similar problems with similar fixes. - [XXX] - [XXX] - [XXX] - one individual in this thread had complete power loss while driving down the highway This issue potentially risks stranding customers, and if the hybrid battery continues to bulge increases the risk of fire which could lead to property damage, personal injury, or death. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11671018 — an unverified report by a vehicle owner.
The contact owns a 2024 Hyundai Sonata. The contact stated while driving 35 MPH, the check engine warning light illuminated. The vehicle was taken to the dealer to be diagnosed. The vehicle was diagnosed with fuel injector failure. The vehicle was repaired but the failure persisted. The contact stated that on another occasion, the check engine warning light illuminated, and the contact turned off the vehicle. The contact restarted the vehicle after several minutes and the vehicle started working properly. The vehicle was then taken to a dealer and was diagnosed with fuel consumption failure. The vehicle was repaired for the most recent failure. The contact then stated that the check engine warning light illuminated on and off a third time. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 15,395.
NHTSA complaint #11642278 — an unverified report by a vehicle owner.
Literally for years I have been taking my car in to Rick Case Hyundai with the complaint of smelling gas even when the car was parked for long periods. Each time they said they fixed with different items. Gas cap, a part on the catalytic converter, etc. The problem never resolved but I noticed it only happened when the tank was more than half full. I got a video of gas dripping out underneath and took the car to Rick Case and gave them the video. My car has been there ten days because they first tried to say it was a seal on the fuel pump. This time I said that seems unlikely cause that only happens when tank is full and persists even after car is parked many hours. Now they report they found a pinhole leak in the gas tank. I will upload the video if this form allows. This does not appear to be a pinhole leak to me. I first noticed this around 2019. Unfortunately the video is MP4 and I cannot upload it.
NHTSA complaint #11631932 — an unverified report by a vehicle owner.
On July 15th I was driving away from work and my car suddenly stopped accelerating. I was able to get it towed to a body shop I previously had it repaired at. They said the battery system was blowing a fuse when it would become undrivable. They took it to the local Hyundai dealership where they applied a new software update related to the battery management system. This did not solve the issue, it continues to stop while in traffic and the dealership refuses to do anything to figure out the cause.
NHTSA complaint #11610285 — an unverified report by a vehicle owner.
The contact owns a 2012 Hyundai Sonata Hybrid. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power and the low battery warning light illuminated. In addition, the contact heard a rattling sound coming from the engine before the engine seized. The vehicle was towed to the dealer where it was diagnosed with a failed hybrid system and that the hybrid system needed to be replaced. The contact was also informed that the transmission was not the original transmission, and the cooler was damaged. The manufacturer was not made aware of the failure. The failure mileage was approximately 145,000.
NHTSA complaint #11588669 — an unverified report by a vehicle owner.
The contact owns a 2016 Hyundai Sonata Hybrid. The contact stated while driving approximately 60 MPH, the check engine warning light illuminated, and the message "Check Hybrid System, Turn Off the Engine" was displayed, and the vehicle was shaking while decelerating. The vehicle was towed to the dealer where it was diagnosed with the Technical Service Bulletin: 198. The Technical Service Bulletin was completed; however, the failure recurred. The vehicle was towed to the same dealer where it was diagnosed with a drained battery and catalytic converter failure. The vehicle was repaired; however, the failure recurred. The vehicle was towed to the same dealer. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 147,000.
NHTSA complaint #11584421 — an unverified report by a vehicle owner.
In May, the engine completely failed as I was driving on the freeway, without cause. It had to be towed to the dealership where luckily the engine was replaced under warranty. Less than 6 months later, the HEV and CEL warning lights came on as I was commuting to work via highway. The car was very low powered, hard to accelerate, and immediately decelerated whenever I started to let off the gas pedal. It struggled to go at or above 60-65 mph. The freeway speed was 70 mph and it was a safety risk for the car to power down. Dublin Hyundai could not replicate the problem, simply recharged the battery and said I was good to go. Less than 1 week later, the exact same thing happened as I started on a road trip. I had to return the car home and get it towed to Stockton Hyundai for diagnosis. This is car is only 6 years old, has been routinely maintained, and just hit 100k miles, for which Hyundai is denying any repair assistance even though there is a lifetime hybrid battery warranty.
NHTSA complaint #11556999 — an unverified report by a vehicle owner.
The contact owns a 2015 Hyundai Sonata Hybrid. The contact stated while stopped in traffic, the vehicle independently jolted with a message indicating a Hybrid System safety failure. Additionally, there was a message to stop driving the vehicle with an alarm sounding. The contact veered to the side of the road. The contact was able to continue driving. The contact received notification of NHTSA Campaign Number: 23V651000 (Service Brakes, Hydraulic) the following day; however, the part to do the recall repair was not yet available. The contact stated that the failure recurred while driving. The contact veered to the side of the road. The vehicle was then taken to an independent mechanic, where it was test-driven; however, the mechanic was unable to duplicate the failure. The local dealer was contacted and informed the contact that the earliest availability was on December 23, 2023. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the failure. The failure mileage was approximately 97,500. VIN tool confirms parts not available.
NHTSA complaint #11556073 — an unverified report by a vehicle owner.
Since a few weeks after buying the car new, the battery dies and self resets every few weeks on average. No error codes occur, but the car had clearly lost power while parked, indicating an issue with power management. For the last could months, car now has 26-27K miles and is 21-23 months old, it had mostly stopped resetting. It now is dead when I go out to it, even after only a couple hours of it being parked at night or during the day. I have to manually access the car and use the battery reset button. They observe no error codes. I have read other people have the failure while driving and fear and electrical issue could be a fire hazard. At the very least, it is a personal safety issue in making me take time to access my car, which could increase my risk of being attacked while trying to get into my car safely. It has occurred 5 or 6 times since August 21, most recently on October 8th and 9th.
NHTSA complaint #11551501 — an unverified report by a vehicle owner.
Battery keeps dying randomly. Approximately once every other week and I drive 12k miles a year… dealership reassures me it’s find. Found numerous reports of other Sonota Hybrid users experiencing a similar issue.
NHTSA complaint #11549715 — an unverified report by a vehicle owner.
Multiple Error codes popped up on Multiple occasions. Lost power and last code was "Check Hybrid System Shut off Engine" HEV System Error. Battery, Engine, Collison, and Maintenance Error Lights showing on Dashboard. 06/ 22 - Dealership inspected and worked on Safety Recalls only. Nothing else was found. 10/22 - Fix Finder report showed Error code P0455. Vehicles reset itself somehow over the weekend. No issues on Monday morning. 11/22 - Lost all power. Towed to Dealership. They reset codes P0455 and P0456. Test passed w/ no further issues. 07/09/2023 - Driving 65mph and loss power. Multiple Error codes. Slowed to 20mph and made into driveway. HEV Shut off Engine came on as I stopped.
NHTSA complaint #11531219 — an unverified report by a vehicle owner.