2021 Hyundai Sonata Complaints

POWER TRAIN — Filed 09/23/2026

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)

FUEL/PROPULSION SYSTEM — Filed 09/23/2026

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

FUEL SYSTEM, GASOLINE — Filed 09/15/2025

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.

POWER TRAIN — Filed 01/26/2023

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

POWER TRAIN,UNKNOWN OR OTHER,FORWARD COLLISION AVOIDANCE — Filed 04/15/2026

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

FUEL SYSTEM, GASOLINE — Filed 12/15/2025

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.

FUEL/PROPULSION SYSTEM — Filed 08/12/2026

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.

ELECTRICAL SYSTEM — Filed 08/01/2026

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.

FUEL/PROPULSION SYSTEM — Filed 08/07/2026

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.

FUEL SYSTEM, GASOLINE — Filed 07/28/2026

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.

POWER TRAIN,ENGINE — Filed 07/31/2026

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

UNKNOWN OR OTHER — Filed 07/22/2026

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.

FUEL/PROPULSION SYSTEM — Filed 07/25/2026

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.

FUEL SYSTEM, GASOLINE — Filed 07/27/2026

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.

UNKNOWN OR OTHER — Filed 07/18/2026

The panoramic sunroof spontaneously exploded while driving without any external impact

SERVICE BRAKES — Filed 01/15/2026

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.

ENGINE,FUEL/PROPULSION SYSTEM — Filed 06/22/2026

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.

AIR BAGS,FORWARD COLLISION AVOIDANCE — Filed 08/06/2025

During a front end collision the car did not auto brake and the air bags did not deploy. The car has been totaled and is currently at a dealership for insurance appraisal.

UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM — Filed 06/08/2025

I bought this car in June 2013 for its safety and its Amazing warranty and all the features that it has Hyundai manufacture had an obligation as a consumer service and failed to send notification of any recalled to us in regards to a recall High pressure, fuel pump, and fuel rail Fuel system engine, gas tank This is a product of liability and negligence on time but they failed to take responsibility and comply with federal laws. I was driving with my family in the car when this car was a ticking Time bomb not even being aware of the Death trap on wheels. We ended having towed our home and then to then had to make a call next day and have it towed to Hyundai service center While we were driving this happen, where we heard two loud pops the gas gauge went down from 200 something to 80 engine lights came right up the backseats were heating up under my son seat in the back stated he felt waves as the backseat was getting hotter, we pulled over to a gas station and that’s when we had to call called O’Reillys and then we called a mechanic friend which stated that he ended up looking up the car and stated please pull over and get out car and called the Hyundai manufacture that there was a recall that’s the only way we found out other than that no prior incidents, then called the service technician of Hyundai i called amd complaint with the Honda manufacture corporate. They have failed to take the responsibility for this and they should be ashamed and take their accountability for this we could’ve died and anyone else around us on road as we drive this car daily The car was a higher risk of a ticking time bomb stated by the Hyundai service center technicians. this is an nere to miss accident narrowly avoid catastrophe

ENGINE — Filed 05/08/2024

I purchased this vehicle brand new. It is still under factory warranty. It has approximately 14k miles on it. I have followed all recommended maintenance procedures. During a routine maintenance appointment at the dealership (Vancouver Hyundai 6802 NE 40th Street, Vancouver WA 98661) they identified a catastrophic engine failure due to internal component deterioration and the engine needs to be replaced. They have had my vehicle in their possession since [XXX] of this year for a total of 134 days. I have a case number at Hyundai # [XXX]. They have not been helpful in providing any information and as of now, I do not know when they even expect to receive a new engine. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM — Filed 03/08/2024

WAS PARKED IN BANK PARKING LOT. STARTED ENGINE, PLACED CAR IN REVERSE AND CAR ACCELERATED AT A VERY HIGH RATE OF SPEED. (LIKE I WAS IN A DRAG RACE!!) APPLIED BRAKES, WHICH DID NOT SLOW THE VEHICLE DOWN. DID NOT STOP UNTIL I RAN INTO A PARKED CAR. WHOLE INCIDENT TOOK JUST SECONDS. CAR HAD BEEN IN FOR REGULAR SERVICE AT THE DEALERS ON [XXX]. NOW HAS 16,597 MILES ON VEHICLE. CAR TO BE SERVICED AT RACHELS COLLISION, 720 S NOVA ROAD, DAYTONA BEACH, FL ON MONDAY [XXX]. IF I HAD NOT RAN INTO A PARKED CAR, I WOULD HAVE ENTERED [XXX] IN DAYTONA BEACH SHORES, FL WHICH WAS CROWDED WITH MOTORCYCLES.... FRIDAY NOON DURING BIKE WEEK. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

UNKNOWN OR OTHER — Filed 12/06/2023

1. Vehicle Speed Control 2. I was in a friend's driveway with the car in drive with auto hold activated. Car lunged forward and not able to stop it. Ran into a garage door did substantial damage to home owners property. I guess we were lucky the door took the impact. 3. I took to dealer today to report and have appointment to have looked at on January 8th. They have no previous report of this happening. 4. I have contacted my insurance company, but they are just filing a claim. 5. I was talking to my guest and was not looking at the dashboard, but I saw no warning message after the fact.

SERVICE BRAKES,FORWARD COLLISION AVOIDANCE — Filed 04/14/2023

Vehicle in front of me stopped. Six car lengths between us. I applied brakes, nothing, I even put my left foot on top of my right foot. There was plenty of time to stop but brake peddle wouldn’t go down, Felt like it was locked. Automatic Brake Sensor didn’t work either. Still waiting for inspection from manufacturer , 3 weeks. Never had any problems prior to this, After accident my warning came on about front collision failure .

AIR BAGS — Filed 01/12/2022

I turned on a highway and had gotten my car up to 45 mph when a deer came out of nowhere and I slammed into it hard back on January 12th. The car only suffered cosmetic damage thankfully, but the air bags did not deploy. I have since then found out that the front air bag crash sensors are in a spot where they are practically useless unless you hit something pretty high up and destroy the headlights in the process. In my opinion, this is a serious safety issue, and when I contacted Hyundai about it, all they told me was to go to the dealership for inspection. I have pictures showing that the crash sensors are located at and not where they should be, and if you open the hood, the wiring for the sensors is right in your face. I still have high anxiety knowing that if I get into another accident, they may not deploy due to their location. At least the car is still drivable and no structural damage or alignment issues are there. As you can see in the pictures the sensors are close to where the hood closes at the top support bar.

PARKING BRAKE,UNKNOWN OR OTHER — Filed 06/12/2021

The contact owns a 2021 Hyundai Sonata. The contact stated that after driving out of the garage and parking in the driveway with the engine idling and remote smart parking assist feature activated, 6 minutes later the vehicle suddenly began to slowly roll forward into the garage area making contact with a second vehicle that was parked in the garage before crashing into the back of the garage wall and stopping. During the incident, no injuries were reported, and no police report was filed. The vehicle was taken to the local dealer who was unable the duplicate the failure. The manufacturer was also notified of the failure. The approximate failure mileage was 1,400.