Hyundai Sonata Complaints (2021)

190 consumer complaints on file.

#11773269October 23, 2026
ELECTRICAL SYSTEM
The left turn signal works intermittently. It has now stopped working about 90% of the time. The multi-function switch was replaced 3 times and I am still having the issue. The signal won't work on the exterior and it won't light up on the interior dash either. This is creating an unsafe driving environment which increases crash rates. Multiple vehicle owner with the same make/model/year are experiencing this issue, which I have found during research.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11767539September 28, 2026
POWER TRAIN
My 2021 Hyundai Sonata N Line suffered a catastrophic, sudden total loss of drive power while operating at speed on a public roadway, creating an immediate crash hazard. The vehicle lost forward propulsion and the gear selector flashed a blinking 'R' when reverse was attempted. The vehicle was towed to an authorized dealer, [XXX] Hyundai Southtowne, where their factory GDS tool pulled transmission code P283601 (Shift Fork 'B' Position Circuit). This matches the exact critical safety failure path targeted by Federal Safety Recall 236 (NHTSA Campaign 22V-746) for the 8-speed wet-DCT high-pressure electric oil pump circuit failure. The vehicle previously received the 2022 software patch, but the underlying physical hardware has now actively degraded. The dealership is attempting to deny the federal safety recall remedy based on the vehicle's high mileage. An active corporate consumer affairs investigation has been opened under Case #XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11766388September 23, 2026
FUEL/PROPULSION SYSTEM
DESCRIPTION OF SAFETY DEFECT & IMMEDIATE HAZARD:My 2021 Hyundai Sonata SEL is currently exhibiting the most severe, catastrophic symptoms of the fuel tank expansion defect covered under NHTSA Campaign 25V796000. The fuel tank has expanded so drastically that it physically warped the structural interior of the cabin, violently popping the rear passenger seat completely out of its assembly while the vehicle was in motion. Furthermore, there is a constant, heavy, raw gasoline odor inside and around the vehicle. The vehicle is a documented, active fire, explosion, and vapor inhalation hazard. It is currently physically located at Sterling Hyundai in Lafayette, LA.DESCRIPTION OF MANUFACTURER NON-COMPLIANCE & REFUSAL TO REMEDY:Hyundai Motor America and Sterling Hyundai are in direct violation of their legal obligation to provide a safe, accessible remedy or interim safety accommodations under federal recall guidelines. An Executive Case Manager from Hyundai Corporate has officially refused to provide a direct-billed rental vehicle or a dealer loaner.Initially, a third-party rental vehicle was provided. However, that vehicle was compromised in an accident and wrecked through absolutely no fault of my own. Despite my lack of fault, Hyundai Corporate and the dealership are now explicitly using that accident to refuse any further direct-billed rental accommodations or dealer loaners.Instead, they are demanding that I pay out-of-pocket for a rental vehicle at a rate of $60/day for a repair process expected to take multiple weeks, knowing I do not possess the upfront financial means to cover these costs. By imposing this insurmountable financial barrier due to an accident I did not cause, Hyundai has effectively stranded me. Because I must maintain my livelihood and have no other means of transportation, Hyundai’s bad-faith refusal to direct-bill an accommodation is actively forcing me to retrieve and operate a verified, explosive fire hazard.REMEDY SOUGHT:I request that the NH
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11765198September 18, 2026
POWER TRAIN, FUEL/PROPULSION SYSTEM
My Lincoln Nautilus (~9,180 miles) logged 6 "Powertrain Malfunction / Reduced Power" alerts in the [XXX] telematics system between XXX (XXX at 7:59 PM and 8:16 PM; XXX at 1:07 PM and 1:39 PM; XXX at 11:16 PM; and XXX at 10:56 AM). Out of the 6 logged events, I experienced severe loss of motive power during two of them. On XXX, while driving 70 mph on I-95, the vehicle completely lost all propulsion. Coasting without power, I was unable to pull fully onto the shoulder, leaving the car partially stuck in active traffic and narrowly escaping a high-speed collision. Once stopped, the vehicle failed to recognize that it was in Park, causing the electronic parking brake to lock without releasing, which severely delayed towing recovery. The vehicle was towed to a Lincoln dealership in [XXX], whose service department was closed. Upon arrival, the vehicle suffered a complete electrical blackout; the key fob would not unlock the doors, requiring physical key entry. A sales representative provided a jump box, allowing me to start the car, drive back to [XXX], and deliver it to Cavalier Lincoln Ford in [XXX] between 5:00 PM and 7:00 PM on XXX. Cavalier Lincoln Ford stated they could not reproduce the malfunction. The vehicle and its electronic records remain available for inspection upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11765311September 18, 2026
FUEL/PROPULSION SYSTEM
The vehicle was brought to an authorized Hyundai dealer to have Service Campaign TBH and 94B completed. These campaigns were explicitly designed to prevent known mechanical defects (cracked EHRS assemblies and high-voltage battery errors). The software patches failed to protect the vehicle. The physical hardware has now catastrophically failed exactly as predicted by the campaign, resulting in extreme engine overheating and a physically swollen high-voltage battery pack. Hyundai is refusing to cover the cascading physical damage caused by their own failed campaign remedy, leaving me with an active safety and fire hazard. FUEL/PROPULSION SYSTEM" and explicitly state that the vehicle experienced an unchecked thermal event due to an ineffective corporate software update (Campaign TBH / 94B). All documents I have supporting this will not fit in this upload limit.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11765048September 17, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign: 25V796000 (Fuel System, Gasoline); however, parts were on back order. The contact stated that while driving at an undisclosed speed, the vehicle jerked with an abnormal gasoline odor inside the vehicle. An unknown warning light was temporarily illuminated. Upon further inspection, the contact became aware that the fuel level had dropped. The vehicle was taken to a local dealer where it was diagnosed with an expanded fuel tank. The contact stated that the O2 sensor, spark plugs, and ignition coils were replaced by a local independent mechanic; however, the failures persisted. The contact had headaches while driving the vehicle. Medical attention was not needed. The manufacturer was made aware of the failure. The failure mileage was approximately 100,000.
Crash:
No
Fire:
No
Injuries:
1
Deaths:
0
#11764277September 15, 2026
POWER TRAIN
Transmission replaced twice and all of them continue to fail. Several Hyundai service centers are unable to determine the cause and are only able to update/relearn and replace whenever they are able to replicate the issue. The issue is that at a cold start, the car makes a popping sound, jerks and shakes. The car hesitates to accelerate. You can hear the noise of acceleration but RPM does not go past 3 and MPH doesn't go past 30mph. I'm unable to upload docs because of the upload limit. If there's another way to send docs, please let me know
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11759867August 26, 2026
FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL, POWER TRAIN, UNKNOWN OR OTHER
Massive loss of coolant in closed loop cooling system Heat soak. Fail safe mode
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11758588August 21, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); however, the part to do the recall repair was not yet available. The contact stated that while driving at an undisclosed speed, the vehicle independently accelerated and decelerated while the accelerator pedal was depressed. The check engine warning light was illuminated. The vehicle was towed to a local dealer where it was diagnosed with an expanded frame due to an expanded fuel tank. The vehicle was deemed too expensive to repair per the local dealer and was towed for a buy-back. The manufacturer was made aware of the failure, but no assistance was provided. The failure mileage was approximately 55,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11757244August 16, 2026
FUEL/PROPULSION SYSTEM
I took my vehicle in for the safety recall due to an expanding fuel tank on 08/03/2026. I received my vehicle back on 8/12/2026. Hyundai performed an improper repair on the vehicle that will not correct the fuel tank expansion. They replaced the same check valve that was replaced last time I brought the vehicle in for recall on 11/20/2024 repair order # 107221 at Jones Hyundai of Belair. This valve did not and will not correct the fuel tank expansion issue. The expansion issue is caused by fuel getting past the check valve and entering the purge control system. The correct repair is to replace the fuel tank and the purge control system, as the check valve has already allowed fuel to bypass it and enter the system causing the expansion issue. . Replacing the valve that failed & allowed fuel into the system & caused the tank to expand will not correct the issue caused by the failed valve. My fuel tank has not decompressed. I still have the same problem I brought the vehicle in for because the repair Hyundai advised NHTSA on was NOT performed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755570August 7, 2026
FUEL/PROPULSION SYSTEM
Gas tank expansion and pcv melted. Car smells like gas when I was driving earlier, and my garage was flooded with the fumes of gasoline.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755451August 7, 2026
ELECTRICAL SYSTEM
The Left blinker switch keeps going in and out, working about 50% of the time. Both the light and the blinker sound do not turn on. When getting it checked out at an auto repair shop, the maintenance tech said this was more and more common for 2021 sonatas and it was not due to anything I did. It was a multifunction switch problem.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755133August 5, 2026
ELECTRICAL SYSTEM, ENGINE
The vehicle experiences sudden, complete electrical power loss while driving at speed on highways and city streets or on the parking. All digital displays turn off, the engine shuts down, and power-assisted steering and braking are instantly lost without prior warning, presenting an extreme collision risk. The issue first occurred in August 2025 at approximately 48,000 miles and was taken to an authorized Hyundai dealer in Michigan for warranty repair. The dealer held the vehicle for over 30 days but failed to correct the defect. The identical power failure has continued and recently escalated to daily occurrences. A second Hyundai dealer (Pacifico Hyundai, Philadelphia, PA) diagnosed an intermittent open circuit in the engine wiring harness but Hyundai Motor America refuses to repair the vehicle under warranty, claiming 'outside influence' without providing evidence. Driving a hybrid vehicle that randomly cuts all power in live traffic is a life-threatening safety hazard. Hyundai Motor America has failed to rectify this critical safety defect.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754791August 4, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the fuel gauge indicated that the tank was half full. The contact stated that the gauge erroneously indicated that the tank was empty, and the check engine warning light was illuminated. The vehicle was driven to the gas station, and while attempting to refuel the vehicle, the fuel did not go into the tank. The vehicle was towed to the residence. The vehicle was later towed to the dealer, where it was diagnosed with a failed fuel system and a failed fuel tank. The contact was informed that the fuel system and fuel tank needed to be replaced. The vehicle was not repaired. The contact was informed that the failure was associated with the unrepaired recall. The contact was informed that the vehicle was a fire risk. In addition, the contact was informed that there was a hole in the fuel tank that caused the fuel to leak out of the fuel tank. The contact was informed that the parts were ordered to repair the vehicle. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline). The manufacturer was not made aware of the failure. The failure mileage was approximately 50,200.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754136August 1, 2026
ENGINE, POWER TRAIN
Going down the road driving the car lost power and went in limp mode with no warnings on the dash at all!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753241July 28, 2026
UNKNOWN OR OTHER
1. Component Failed: Panoramic Sunroof Glass Assembly (Structure / Visibility / Glass). Details: While traveling at highway speed on the freeway, the panoramic sunroof glass spontaneously exploded outward without warning or impact from any foreign object. Inspection: I have not had the vehicle repaired yet so it is currently available. I also took a picture of it. 2. Safety Risk: The sudden, loud explosion (sounding like a gunshot) at freeway speeds caused immediate driver distraction and severe disorientation. Shattered tempered glass was mostly restricted from the cabin by the curtain barrier but some rained down into the passenger cabin. Most blew backward onto the highway, posing a major hazard to occupants as well as trailing motorists. Furthermore, this is a recurring defect in our household: my wife experienced an identical spontaneous sunroof explosion on her 2024 Hyundai Palisade, demonstrating a pattern of hazardous glass failures across multiple late-model Hyundai vehicles. 3. Reproduced or confirmed: I have not had it inspected by anyone. I am awaiting quotes for repairs. I have taken a picture of the vehicle that has not been driven since the incident. 4. Inspection: No one else has inspected it. I have a picture and can take more as needed. Hoping to not have to drive it until I take it to a shop for repairs. It has been reported to a dealership, but they did not seem too concerned or interested in helping. They insisted that they would not give a repair quote until I drove it the 20 miles for them to inspect. 5. Any Warning: No warning. There were no warning lights, abnormal noises, visible cracks, or previous symptoms prior to the sudden explosion. The failure occurred completely spontaneously under normal highway driving conditions.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753130July 27, 2026
FUEL/PROPULSION SYSTEM
Engine revving at a complete stop. Surging engine while braking. I was forced to put into neutral when stopping. I had check engine prior that read P049D85. It went away. The Hyundai dealer said to be the EGR valve. Nick Hayes at D'Arcy Hyundai and Hyundai Motor America (HMA) agreeing to a 75% goodwill split of cost to repair.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753027July 27, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (FUEL SYSTEM, GASOLINE); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The vehicle was taken to the local dealer, and the contact was informed that the fuel tank was swollen and needed to be replaced. The vehicle was not yet repaired. The failure mileage was 80,484.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11752333July 23, 2026
UNKNOWN OR OTHER
The panoramic sunroof spontaneously exploded while driving without any external impact
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11747445June 30, 2026
SERVICE BRAKES
The contact owns a 2021 Hyundai Sonata. The contact stated that while driving 10 MPH and attempting to make a right turn, the brakes independently activated. Neither the dealer nor an independent mechanic was contacted. The check engine warning light was illuminated. The contact stated that the failure had occurred on several occasions. The vehicle was taken to the dealer and an independent mechanic to be diagnosed. The manufacturer was not notified of the failure. The approximate failure mileage was 42,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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