2021 Hyundai Sonata

134 complaints on file, page 1 of 7.

1. Filed Sep 28, 2026Failure Sep 23, 2026Stansbury park, UTPower 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)

   NHTSA complaint 11767539
2. Filed Sep 23, 2026Failure Sep 23, 2026Lafayette, LAFuel/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

   NHTSA complaint 11766388
3. Filed Sep 17, 2026Failure Sep 15, 2025100,000 milesLafayette, LAFuel system, Gasoline1 injured

   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.

   NHTSA complaint 11765048
4. Filed Sep 15, 2026Failure Jan 26, 2023Dallas, TXPower 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

   NHTSA complaint 11764277
5. Filed Aug 26, 2026Failure Apr 15, 2026Venice, FLAdaptive cruise control, Power train, Unknown or other

   Massive loss of coolant in closed loop cooling system Heat soak. Fail safe mode

   NHTSA complaint 11759867
6. Filed Aug 21, 2026Failure Dec 15, 202555,000 milesLindenhurst, ILFuel 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.

   NHTSA complaint 11758588
7. Filed Aug 16, 2026Failure Aug 12, 2026Rosedale, MDFuel/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.

   NHTSA complaint 11757244
8. Filed Aug 7, 2026Failure Aug 7, 2026Dallas, TXFuel/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.

   NHTSA complaint 11755570
9. Filed Aug 7, 2026Failure Aug 1, 2026Columbus, OHElectrical 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.

   NHTSA complaint 11755451
10. Filed Aug 4, 2026Failure Jul 28, 202650,200 milesJamaica, NYFuel 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.

    NHTSA complaint 11754791
11. Filed Aug 1, 2026Failure Jul 31, 2026Lake Charles, LAEngine, Power train

    Going down the road driving the car lost power and went in limp mode with no warnings on the dash at all!

    NHTSA complaint 11754136
12. Filed Jul 28, 2026Failure Jul 22, 2026Kaysville, UTUnknown 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.

    NHTSA complaint 11753241
13. Filed Jul 27, 2026Failure Jul 25, 2026Plainfield, ILFuel/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.

    NHTSA complaint 11753130
14. Filed Jul 27, 2026Failure Jul 27, 202680,484 milesRosedale, MDFuel 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.

    NHTSA complaint 11753027
15. Filed Jul 23, 2026Failure Jul 18, 2026Centreville, VAUnknown or other

    The panoramic sunroof spontaneously exploded while driving without any external impact

    NHTSA complaint 11752333
16. Filed Jun 30, 2026Failure Jan 15, 202642,000 milesBoynton Beach, FLService 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.

    NHTSA complaint 11747445
17. Filed Jun 24, 2026Failure Jun 22, 2026Lexington, SCEngine, Fuel/propulsion system

    At approximately 130,000 miles, vehicle developed and internal coolant leak caused by a failed Exhaust Heat Recovery System (EHRS) in the center muffler assembly, matching TSB 23-EM-009H - a known manufacturing defect documented by Hyundai. Coolant has been slowly leaking internally into the exhaust system. The authorized Hyundai dealership initially failed to diagnose the internal leak and told me there was no leak and wanted to send me home. After pushing back, the internal leak was confirmed. If not caught, this defect could result in engine overheating or complete engine failure without warning. Hyundai Motor America has denied goodwill coverage despite this being a documented manufacturing defect.

    NHTSA complaint 11746137
18. Filed Jun 1, 2026Failure Sep 3, 2022Cumming, GAPower train

    The vehicle has experienced repeated transmission and Electronic Oil Pump (EOP) failures resulting in loss of propulsion, loss of acceleration, and transmission-related malfunctions. The vehicle currently has approximately 69,000 miles. On September 3, 2022, the vehicle lost propulsion while traveling approximately 31 MPH in traffic and would not respond normally to accelerator input. This created a dangerous situation and increased the risk of a collision. On the same date, while backing out of a parking space, the vehicle displayed a "Shifter System Malfunction" warning message and unexpectedly stopped while in reverse. The vehicle had to be powered off before it would operate again. Following these incidents, the vehicle was towed to a Hyundai dealership and the transmission was replaced in September 2022. Despite the transmission replacement, the vehicle continued experiencing issues involving the same system. The Electronic Oil Pump (EOP) was replaced in 2023 and again in 2024 due to recurring transmission-related concerns and diagnostic codes. In 2026, the check engine light returned and the vehicle was again diagnosed with a transmission-related failure. The dealership determined that the transmission requires replacement for a second time despite the previous transmission replacement and two separate EOP replacements. Internally, Hyundai has since revised its repair guidance for this condition, suggesting that prior repair procedures may not have fully addressed the underlying defect. The repeated failures of the transmission and EOP system despite multiple repairs suggest an underlying defect that has not been corrected. These failures create a significant safety risk because the vehicle can unexpectedly lose propulsion or fail to accelerate while operating in traffic. The vehicle is available for inspection upon request.

    NHTSA complaint 11741226
19. Filed Jun 1, 2026Failure Mar 23, 2026Clarksville, TNElectrical system, Engine

    The car will idle high around 1200 rpms. The car will most of the times fix the issue when you turn the car off and back on but it will start again after driving. This is a known issue with the car. I have had the egr valve replaced since it will pop up the codes P240F and P049 for egr slow response and control position exceeded learning limit but the problem came back within two days. I did find a forum that deals with the joint connector repair but this needs to be a recall as I have come across many people who have this problem and paying out of pocket to fix it.

    NHTSA complaint 11741201
20. Filed May 22, 2026Failure Mar 24, 2026Lynchburg, VAFuel/propulsion system

    I took my car to dealer to repair recall. Dealer told me if it failed they would keep car and report stolen if I tried to take it. They failed it. I didn't trust them based on their report it stolen statement. I had the police get my car back. I took it to another dealer where it passed recall easily. I believe they wanted my car for a customer, and tried to get away with this ruse.

    NHTSA complaint 11739443