2021 Hyundai Sonata Problems & Owner Complaints

Engine 34 1 crash

“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 infor…”
NHTSA complaint #11615509, 2024 · crash

“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, 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 wa…”
NHTSA complaint #11746137, 2026

Unknown Or Other 31 3 crash 5 injury

“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 th…”
NHTSA complaint #11668446, 2025 · 5 injury(ies)

“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 MOTORCYCLE…”
NHTSA complaint #11576439, 2024 · crash

“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.”
NHTSA complaint #11559210, 2023 · crash

Power Train 22

“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, 2026

“P0471 code before 55k miles even after repair is made”
NHTSA complaint #11721861, 2026

“Vehicle suddenly lost heat in 30 degree weather. No warnings, check engine light, or temperature gauge indicators came on. Lucky made it to a parts store and found out I was extremely low on coolant. Bought coolant and put it in. Made it back to the house and was immediately low again. No visible leaking. Oil was completely fine (1 gallon of coolant would have have left some kind indicator). Realized it was more than likely the ehrs. If this happened during the summer, my engine could have blown due to a poor design causing a major accident.”
NHTSA complaint #11718194, 2026

Fuel/Propulsion System 18 1 crash 5 injury

“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 th…”
NHTSA complaint #11668446, 2025 · 5 injury(ies)

“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 MOTORCYCLE…”
NHTSA complaint #11576439, 2024 · crash

“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, 2026

Electrical System 16

“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, 2026

“My 2021 Hyundai Sonata Limited Hybrid 12v battery has started to die randomly. My car is currently with the Hyundai dealer to confirm if this will be a warranty claim. Searching online, I have found other posts of people complaining about a similar issue with their 2021 Hyundai Sonata Hybrid.”
NHTSA complaint #11700120, 2025

“Car sits several days at a time. Door locked. 12 volt auxiliary battery goes dead within 60 minutes after driving 60 miles. Happened 6 times in last 6 weeks. Battery is lithium. Dealer looked at car Sept 8. They did cursory check and said my rodent deterrent caused issue. After driving 60 miles. Turned rodent deterrent off. Still have issue. Car resets the 12 volt battery nearly daily. Lithium battery if bad can blow up and cause vehicle fire. Car is parked in car port next to house. If fire, it burns up my house also. This is fire hazard. If the battery is bad, it must be fixed. Car under 10…”
NHTSA complaint #11694723, 2025

Fuel System 10

“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. T…”
NHTSA complaint #11753027, 2026

“The contact owns a 2021 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the engine shuddered and the engine stalled. In addition, the engine seized. No warning lights were illuminated. The contact stated that the vehicle was seized in the middle of the road. The contact stated that while attempting to start the vehicle, the vehicle started. The failure reoccurred. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure. The failure mileage was approximately 1…”
NHTSA complaint #11738864, 2026

“The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); and the vehicle was taken to the dealer for the recall repair; however, the dealer informed the contact that the vehicle was unrepairable, and there was no further information provided. The manufacturer was made aware of the issue, and a case was filed. The manufacturer informed the contact that the field engineers had reviewed the vehicle and advised that a buyback was the best option. Additionally, the manufacturer offered an 8 percent discount on the purchas…”
NHTSA complaint #11725496, 2026

Forward Collision Avoidance 8 2 crash 7 injury

“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.”
NHTSA complaint #11679381, 2025 · crash · 7 injury(ies)

“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 .”
NHTSA complaint #11520558, 2023 · crash

“Will be driving the car and suddenly hear a beep. Then the dashboard will flash with the ABS light engine light tire pressure light check Blindspot sensors, forward collision sensors. once all the lights appear on the dashboard, I can no longer accelerate. i’ve cleaned the throttlebody. I’ve replaced the gas pedal and it’s still kicking back the same code it still does it the same identical thing. It’s given out on me three times since December with an infant in the car. We are now in February.”
NHTSA complaint #11714874, 2026

Visibility/Wiper 8

“The internal core of the Exhaust Heat Recovery System (EHRS), part of the center muffler/front pipe assembly (#28600-L5210), suffered a catastrophic failure. This allowed approximately 9 gallons of engine coolant to leak directly into the hot exhaust stream. Safety Risk: This failure creates a severe visibility hazard. During acceleration from stop lights and stop signs, the vehicle emits massive, thick clouds of white glycol smoke. The smoke is so dense that it completely obscures the driver's view of trailing vehicles and prevents following drivers from seeing the roadway or my vehicle's bra…”
NHTSA complaint #11727380, 2026

“The EHRS coolant system failed and had a leak causing the coolant to be excessively burned off as thick white smoke. This caused me to not be able to see anything behind me and forced others to stop or slow down dramatically to avoid colliding with me. I had my engine overheat and force me to pull over on the side of an unsafe road because the exhaust system burned off my entire tank of coolant in less than a mile. I have taken this to a Hyundai dealership and they confirmed it was the EHRS system failure and told me it was a fairly known issue with the 2020-2023 Sonata Hybrids. I was told tha…”
NHTSA complaint #11719316, 2026

“The vehicle's HVAC (heating) system failed. It stopped producing heat on one side of the vehicle. My mechanic/dealer diagnosed the issue as a broken component within the HVAC case under the dashboard, requiring full dashboard removal and a repair estimated at over $3,000. This failure prevents the defroster from working properly, which is a major safety hazard as it cannot clear fog or frost from the windshield. A search of online forums and owner communities shows this is a widespread complaint from many other Hyundai owners, often identified as a failed blend door or blend door actuator, w…”
NHTSA complaint #11698349, 2025

Air Bags 4 2 crash 7 injury

“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.”
NHTSA complaint #11679381, 2025 · crash · 7 injury(ies)

“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 th…”
NHTSA complaint #11456267, 2022 · crash

“WE LEASE A 2021 SONATA SEL EQUIPPED WITH AIR BAG SYSTEM FEATURING AN OCS IN THE RIGHT FRONT SEAT. THE PURPOSE OF THE OCS IS TO DISABLE RIGHT PASSENGER SEAT FRONT AIR BAG WHEN IT DETECTS TA CHILD RESTRAINT SYSTEM OR SMALL CHILD IN THE RIGHT FRONT SEAT. RIGHT FRONT AIR BAG IS DISABLED TO PREVENT INJURIES TO A CHILD FROM A RIGHT FRONT AIR BAG INFLATION DURING A CRASH. MY WIFE IS ABOUT 4'10" TALL AND WEIGHS 135#. WHEN SEATED IN PASSENGER SEAT, SHE REQUIRES A CUSHION TO RAISE HER SO SHE CAN SEE OVER DASHBOARD AND OUT SIDE WINDOW. OUR SONATA IS EQUIPPED WITH MANUAL PASSENGER SEAT THAT IS RAISED TO…”
NHTSA complaint #11435886, 2021

Structure 4

“• I experienced trouble with my splash guard being damaged from hanging and scraping the ground about a month after purchasing the vehicle. Also, my hood paint started chipping after a recent cold front experienced in my state earlier this year. Yes it is available for inspection upon request. Regarding the splash guard, not applicable. • It’s was very inconvenient to drive with a portion of my car scraping the ground. I had to be more mindful of my driving in the higher speed limit areas incase the splash guard detached. I had it re-attached multiple times. Regarding the chipped paint, not…”
NHTSA complaint #11730039, 2026

“Sunroof exploded on the highway with no one in-front of me to kick up any rocks or debris.”
NHTSA complaint #11641851, 2025

“I was driving down the highway with my mom, no cracks in any of my windows before any of this by the way. And my sunroof exploded. Huge huge explosion sound. I thought something fell but there was nothing above us.”
NHTSA complaint #11526475, 2023

Visibility 4

“The contact owned a 2021 Hyundai Sonata. The contact stated that while driving approximately 70 MPH, the sunroof suddenly fractured. The contact stated that there was no external cause to the failure. The vehicle was taken to the dealer. The vehicle was not diagnosed nor repaired. The contact decided to trade the vehicle. The manufacturer was not made aware of the failure. The approximate failure mileage was 13,300.”
NHTSA complaint #11513262, 2023

“As I was driving down the road I heard what sounded like a gunshot and glass shattering. Upon getting to my destination I found that my panoramic sunroof had shattered outward.”
NHTSA complaint #11503651, 2023

“The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 21V00M000 (Visibility) however, the part to do the recall repair was unavailable. The dealer was made aware of the issue and confirmed that parts were not yet available. The manufacturer was made aware of the issue. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact had not experienced a failure. VIN tool confirms parts not available.”
NHTSA complaint #11464009, 2022

Lane Departure 3

“Will be driving the car and suddenly hear a beep. Then the dashboard will flash with the ABS light engine light tire pressure light check Blindspot sensors, forward collision sensors. once all the lights appear on the dashboard, I can no longer accelerate. i’ve cleaned the throttlebody. I’ve replaced the gas pedal and it’s still kicking back the same code it still does it the same identical thing. It’s given out on me three times since December with an infant in the car. We are now in February.”
NHTSA complaint #11714874, 2026

“Engine makes rattling and knocking noises. Transmission hesitates and jerks Suspension front struts and rear shocks are bad. Possible the isolators. Having horrible back pain when riding in car. Starter intermittently doesn't work Lane keep assistance goes over small bump in road will make car drive in opposite lane into on coming traffic. Took car to Tameron hyundai in Birmingham on the 29th of December 2025. Told them everything thats going on with the car. They did nothing about any of the issues. Car has 55,000 miles on it as that is when all problems have incurred. 60000 mile Warran…”
NHTSA complaint #11709919, 2025

Service Brakes 3 1 crash

“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 .”
NHTSA complaint #11520558, 2023 · crash

“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, 2026

“Was driving in reverse out of garage and ABS brakes were applied like I hit a patch of ice stopping the car. Released when applied pressure to brake. Then while on highway going 60 miles an hour the emergency brake system went on for no reason applying pressure and red light came on the dash with a left facing arrow. System released within a few seconds but scared me and I still have to drive this car on highway.”
NHTSA complaint #11639354, 2025

Seat Belts 2

“P0471 error comes up off and on, this is recall related but the dealership refuses to address it. The seatbelt has to be clicked 2x in order to stick. Happens with driver side.”
NHTSA complaint #11706868, 2025

“The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, his son complained that the seat belt had tightened and locked and that he was unable to adjust the seat belt. Upon arriving at his destination, the contact stated that attempts to remove the seat belt had failed and the contact decided to cut the seat belt. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 26,450.”
NHTSA complaint #11536091, 2023

Seats 2

“The driver seat motor malfunctioned when pennies got jammed iin the unprotected/exposed seat tracks. Hyundai would not cover the warranty and charged me $2000.00 for repair. After complaining to the Hyundai National customer service they would not consider my point of contention that the unproteted/exposed tracks contributed to the failure. A professional mechanic stated that a fuse should have failed before the motor malfunctioned.”
NHTSA complaint #11699648, 2025

“WE LEASE A 2021 SONATA SEL EQUIPPED WITH AIR BAG SYSTEM FEATURING AN OCS IN THE RIGHT FRONT SEAT. THE PURPOSE OF THE OCS IS TO DISABLE RIGHT PASSENGER SEAT FRONT AIR BAG WHEN IT DETECTS TA CHILD RESTRAINT SYSTEM OR SMALL CHILD IN THE RIGHT FRONT SEAT. RIGHT FRONT AIR BAG IS DISABLED TO PREVENT INJURIES TO A CHILD FROM A RIGHT FRONT AIR BAG INFLATION DURING A CRASH. MY WIFE IS ABOUT 4'10" TALL AND WEIGHS 135#. WHEN SEATED IN PASSENGER SEAT, SHE REQUIRES A CUSHION TO RAISE HER SO SHE CAN SEE OVER DASHBOARD AND OUT SIDE WINDOW. OUR SONATA IS EQUIPPED WITH MANUAL PASSENGER SEAT THAT IS RAISED TO…”
NHTSA complaint #11435886, 2021

Steering 2

“After 9 months of ownership, on at least five (5) instances, the car has the following things happen at the same time: 1) all warning lights on the dashboard activate, 2) the battery discharge warning light activates, a loss of power steering, no speedometer, no cameras (rear or front), no AC, and all the safety functions are disabled including but not limited to: Forward Collision Warning, Parking Collision Warning, Automatic Emergency Braking, Lane Departure Warning, Rear Cross Traffic Warning. Yes, the car is available for inspection upon request. Safety is at risk by the loss of power st…”
NHTSA complaint #11511856, 2022

“I leased a 2021 Sonata, and the Car has been a nightmare. My Car has been serviced by the dealership twice for a steering wheel that will not stop making noises. I am very concerned for my safety in this Car. The Wheel becomes hard to move. Also, last year, the Car was in the shop for four months while the forward collision sign needed to be fixed. The Car stopped twice. I am terrified to drive this car; it only has 9,200 miles.”
NHTSA complaint #11496631, 2021

Vehicle Speed Control 2

“Vehicle began to lose power while on highway. The loss of power occurred for a few seconds, then came back. Shortly after, the RPM began changing uncontrollably. Tried shifting to manual control using paddle shifters and was able to maintain steady RPM until vehicle software switched back to automatic and RPM swung crazy again. Endangered other vehicles on road due to loss of power and fluctuations of transmission. Once parked, vehicle did not change to neutral, drive, reverse. Both manufacturer and insurance are/have reviewed vehicle and are working on a fix. No warning lights. Only indicatio…”
NHTSA complaint #11585188, 2024

“Since we purchased this brand new vehicle, we have had in the dealership service department at a minimum of 5 times for same issue. The vehicle accelerates while stopped at a light so we have to put it in neutral to keep it from accelerating. Once we take out of Neutral and release the break, the vehicle accelerates rapidly without stepping on the gas pedal. The computer system always comes on warning that we need to take to dealership because there are engine problems. Then it goes off and comes on again. We have contacted Hyundai to file a complaint and it has gone no where. We have taken it…”
NHTSA complaint #11485887, 2022

Engine And Engine Cooling 1

“The contact owns a 2021 Hyundai Sonata. The contact stated while driving 15 MPH, the contact noticed that the passenger’s side rear seat level had become elevated. The contact stated that his daughter who was seated in the child seat head had started touching the top of the sunroof. The contact became aware of a gasoline odor coming from the engine. The contact also became aware that the vehicle was consuming an abnormal amount of gasoline. There was no warning light illuminated. The vehicle was taken to the dealer however, the diagnostic test result was undisclosed. The dealer was unsure of h…”
NHTSA complaint #11590388, 2024

Parking Brake 1 1 crash

“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…”
NHTSA complaint #11425935, 2021 · crash

Suspension 1

“Engine makes rattling and knocking noises. Transmission hesitates and jerks Suspension front struts and rear shocks are bad. Possible the isolators. Having horrible back pain when riding in car. Starter intermittently doesn't work Lane keep assistance goes over small bump in road will make car drive in opposite lane into on coming traffic. Took car to Tameron hyundai in Birmingham on the 29th of December 2025. Told them everything thats going on with the car. They did nothing about any of the issues. Car has 55,000 miles on it as that is when all problems have incurred. 60000 mile Warran…”
NHTSA complaint #11709919, 2025