Complaint volume
115 consumer-submitted complaints are matched to this model year. Treat the count as a research signal, then read the actual summaries for repeated symptoms.
Complaint records
2021 Hyundai Sonata Complaints
115 consumer-submitted complaints on record for the 2021 Hyundai Sonata, grouped by component category.
115 Total complaints
7 Crash reports
0 Fire reports
2 Injury reports
Complaint data reflects consumer-submitted reports. A complaint is not proof
of a defect, recall, or manufacturer fault. Enriched severity fields come
from official bulk records when the complaint can be matched by ODI number.
Buyer interpretation
How to use these complaints before buying
Complaint records are most useful when they turn into inspection points, seller questions, and comparison checks against nearby model years.
Pattern to inspect
The most common categories are unknown or other, power train, engine. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 7 crash reports, 0 fire reports, 2 injury reports, and 0 fatality reports. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 20 complaints, with an average reported failure mileage of 42,019 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to unknown or other, power train, engine?
- Can I see recent maintenance and repair records?
- Has the vehicle ever been towed, involved in a crash, or repaired for the same issue twice?
- Can we also check the recall record for this 2021 Hyundai Sonata?
Used-car checklist
Use these complaints before the test drive.
Build a buyer checklist to turn these issues into questions and inspection points.
2021 Hyundai Sonata
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2021 Hyundai Sonata complaints?
7 Crash
0 Fire
2 Injury
0 Fatality
5 Towed
1 Medical attention
What are the most common 2021 Hyundai Sonata complaint categories?
UNKNOWN OR OTHER 20
POWER TRAIN 12
ENGINE 10
ELECTRICAL SYSTEM 9
FUEL SYSTEM, GASOLINE 7
ENGINE,FUEL/PROPULSION SYSTEM 4
FUEL/PROPULSION SYSTEM 4
POWER TRAIN,ENGINE 4
VISIBILITY/WIPER 4
ELECTRICAL SYSTEM,ENGINE 3
115 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Jan 2025 | POWER TRAIN | 2 years after purchasing a new vehicle, the transmission began to pop and cause the car to jerk upon a cold start, RPM would increase but the speedometer would not go over 20mph. There were no error messages or alerts. I reported it several times, and the dealership technicians could not duplicate the issue and stated that the car was driving as it was designed even after providing video proof. They were later able to partially replicate the issue when the car popped and jerked after a cold start and then replaced the transmission, however, it did not resolve the issue. 1 month after the repair the car started having the same issues. After several trips to the service department, they have still been unable to duplicate the issue even with recent video proof. Based on how the technicians enter notes, the manufacturer refuses to pursue any alternative method for figuring out what is going on. This is risky because my car, upon starting cannot be safely driven and the car will shutter upon stopping at lights sometimes. | Crash: No Fire: No | Unknown |
| Dec 2024 | ELECTRICAL SYSTEM | In June 2024, I was driving my vehicle when I started to smell burning from under the dashboard. As I continued to drive, the smell got worse, and on my way to the dealer, my air conditioner stopped working. I took my car back to the dealer for service, and several days later, I was told that my car needed a hardness connected to several components in the engine compartment. I remember while I was dropping off my car at the dealer, one of the service advisors told me that it was good. I drove to the dealer because the car could have gone on fire. It's now six months later, and they have not fixed my car. I was told they're awaiting parts from Korea to complete the fix. My concern is that this part can cause a fire. Why did Hyundai not recall these vehicles? Hyundai knows about the problem. I was told that I'm not the only one waiting; supposedly, there are 100's more customers waiting for this part. | Crash: No Fire: No | Unknown |
| Dec 2024 | ELECTRICAL SYSTEM,ENGINE | This car has two problems. 2 weeks I was driving on the highway. All the sudden the shutoff and lost all power on the car. Thank god I pulled to the side of the road safely. Turned the car off and turned it back on. The car started to run normal. I took it to mechanic. They scanned the car with their computer. Said the car has no problems. Tested the battery and all other components. No problems found. This happened again yesterday on the highway driving. Car engine shuts off again. The car has engine problems as well. But Hyundai denies to address it. | Crash: No Fire: No | Unknown |
| Oct 2024 | ELECTRICAL SYSTEM,ENGINE | 2021 Hyundai Sonata 59,850 miles RPM jumps to around 1,300 at zero miles on occasion. If I am stopped, at a red light or behind other stopped autos, the vehicle jumps forward when I take my foot off the brake. Because this happens quite often, I am aware of this and keep my foot on the brake until other vehicles are out of the way to avoid bumping into them. When this happens, I can cruise at 30 miles per hour without having my foot on the accelerator, I can slow down or stop by applying the brakes but the engine RPM stays at 1,300. If I stop and shut off the vehicle and restart, the operation goes back to normal but occurs again later. The Hyundai dealer has had the vehicle back 9 times but the issue continues. The first few times, they could not find an issue, I returned to the shop when this was happening and the service manager and a technician observed this condition, the EGR valve was replaced. Was OK for a bit but condition returned, the computer was then replaced. Condition continued. Brought the vehicle back and a scan was done and system “re-learned. After a short time the condition returned. Went back to the service center and they did another scan and another re-learn. Condition returned 4-5 days later. Problem still not resolved. Have 59,850 miles on the vehicle, warranty expires at 60,00 miles. This started around July 1, Now October 5. Waiting for a loaner so the service center can drive it around until the situation occurs and they can bring it in immediately for diagnosis. This is the same issue as reported for the same year vehicle in July 2022. | Crash: No Fire: No | Unknown |
| Sep 2024 | ENGINE,FORWARD COLLISION AVOIDANCE | The contact owns a 2021 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the vehicle lost motive power. Additionally, the Forward Collision Avoidance failed to function as intended. The contact stated that the sensor was braking prematurely. The vehicle was taken to the dealer; however, the failure was not duplicated. The contact stated while driving out of the driveway, the vehicle lost motive power. The vehicle failed to restart. The dealer was contacted and made aware of the failure. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was not made aware of the failure. The failure mileage was unknown. | Crash: No Fire: No | Unknown |
| Sep 2024 | ENGINE | 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) | Crash: Yes Fire: No | Unknown |
| Sep 2024 | ELECTRICAL SYSTEM | Blower motor on 2021 Hyundai Sonata SEL stopped working. Same issue happened on my 2020 Hyundai SEL and currently waiting on my 2020 Sonata to be fixed. Hyundai technician said the wiring harness had a crack and it’s why my 2020 Sonata’s Blower motor stopped working. It’s now three months since they diagnosed and ordered the wiring harness but supposedly it’s still on back order and I’m left with a hot car this entire summer and possibly a cold car come this winter. Now it looks like I will have the same issue with my 2021 Hyundai Sonta. | Crash: No Fire: No | Unknown |
| Sep 2024 | ELECTRICAL SYSTEM | Fuse box has a defect causing the AC blower motor to intermittently not work. Appears to be the result of loose connections between the fuse box and the fuse itself. The receptacle for the fuse is clearly burnt/melting, and appears to pose as a fire hazard as a result. The car is currently in the shop for repair on this part, but won't likely be fixed for a month+. I do have photos of the damaged parts, should it be requested. The car was taken into a Hyundai dealership for repair work in November 2023, and I was told the fuse had blown but that they fixed it. I was never told about the box appearing damaged/melting at that time, or this being a common problem. It worked again till July 2024. Car was just dropped off 9/3, due to backlog of cars at dealership. The only symptom of issue was the AC blower motor would stop working at random. It would turn back on/off while driving. This seems to be due to the loose connections between fuse box and fuse. | Crash: No Fire: No | Unknown |
| Aug 2024 | POWER TRAIN | Issue with DCT transmission. Unknown remedy | Crash: No Fire: No | Unknown |
| Aug 2024 | UNKNOWN OR OTHER | UNKNOWN Wednesday 7-3-24 I was driving on an interstate at night, going approximately 74mph and my car totally powered down and powered back on with no warnings. Everything on the dashboard and display screen went black. This was totally random and has never happened before. I’m a second owner, previously owned by a rental car corporation. I have no idea if there has been previous recalls that have not been repaired or not. | Crash: No Fire: No | Unknown |
| Jul 2024 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | I have been to the dealership on three separate occasions due to the engine misfiring. Two ignition coils have been replaced so far and I recently returned to the dealership for the same issue. This time however, not only did the engine light come on but I went from a full tank to less than a quarter of a tank and the engine is making backfiring sounds. At that time the dealership said that they could not recreate the issue, I got my oil changed and went home. That was a week ago, I am back at the dealership today for the same thing; fuel dumping and backfiring sounds. While at the dealership today it turns out those backfiring noises were the fuel tank expanding so much so that it kept popping the seat up. They deemed the car unsafe to drive and it is currently at the dealership. | Crash: No Fire: No | Unknown |
| May 2024 | ENGINE AND ENGINE COOLING | 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 how to service the vehicle. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 87,000. The VIN was not included. | Crash: No Fire: No | 87,000 |
| Apr 2024 | POWER TRAIN,VEHICLE SPEED CONTROL | 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 indication was minor loss of power prior to incident. Loss of power was not considerable nor for a prolonged period of time. | Crash: No Fire: No | Unknown |
| Apr 2024 | ELECTRICAL SYSTEM | Infotainment center won't switch to Radio. No signal for AM/FM or Satellite. Then HVAC system stopped blowing. No defrost, won't blow heat or AC. Blower motors been tested and works, blower motor resister replaced. Everyone I talk to is saying it's an electrical, connection issue. | Crash: No Fire: No | Unknown |
| Mar 2024 | ENGINE | faulty engine thermostat | Crash: No Fire: No | Unknown |
| Mar 2024 | UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM | 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) | Crash: Yes Fire: No | Unknown |
| Dec 2023 | ENGINE | I was on the highway going 60 mph then all of a sudden my vehicles rpm's jumped way up to 8 and completely lost power was on I-45 in Conroe thankfully I was in the slow lane. I have attached pictures of my dash so I could get proof this time. I had to wait 7 minutes for the car to do anything. It also burned all of my engine oil. So had to buy oil for my vehicle. I just had my oil change 3 weeks ago. This has happened before on on the frontage road a few months ago. I have claims open with Hyundai Customer Care. I have been stating that my engine makes a clicking noise, it hesitates, and seizes all the time. I have had this problem since March of 2021 and I bought the car in January 2021. I know I am not a part of the engine recall but I should be. I am scared to drive it. Hyundai doesn't care one bit. Well enough is enough I will be getting rid of this death trap. If you are looking at Hyundai's don't waste your time or money. | Crash: No Fire: No | Unknown |
| Dec 2023 | UNKNOWN OR OTHER | 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. | Crash: Yes Fire: No | Unknown |
| Oct 2023 | ENGINE | I have a 2021 Hyundai Sonata SEL with a Smartstream 2.5L engine w/ GDI & MPI. I have have always heard a loud knocking noise coming from my engine since I got the vehicle when in park. When you are accelerating it hesitates and you can hear a knocking noise. I have taken it to the dealership multiple times and they were able to feel and hear what I was talking about but ensured me it was fine. Recently it has been a lot worse. On 10/18/2023 I was getting on to the highway from the feeder. I tried to accelerate to about 50 mph and I heard the same knocking noise and my rpms jumped all the way to the top. Then my car suddenly stopped getting on to the highway. It took it about a minute before I could start driving again. Luckily there was no one behind me because it could've been really bad. I got home and looked under the hood and it looked like oil had sprayed out of the engine. You could to see oil splatter on the fender. No one was hurt thankfully. I have been complaining about the knocking and hesitation while accelerating for almost 2yrs. | Crash: No Fire: No | Unknown |
| Sep 2023 | ENGINE | The contact owns a 2021 Hyundai Sonata. The contact stated while driving 45 MPH, the vehicle inadvertently lost motive power in the middle of the roadway and failed to restart. The vehicle was pushed to the shoulder of the roadway, where the failure persisted. No warning lights were illuminated. The vehicle was towed to the dealer, who determined that there was no oil in the engine, causing the engine to seize. The vehicle was then towed to another dealer, who confirmed the diagnostic results. The contact stated that an oil change was performed three days prior to the failure. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was opened. The failure mileage was 44,000. | Crash: No Fire: No Towed | 44,000 |
| Sep 2023 | POWER TRAIN | I took off from the house about 1 mile the car stop in the middle of the road with no warning, lights or anything. Thank God I didn’t get an accident we took the car to the dealer and the dealer telling us it’s not covered by warranty. This is 2021 Hyundai sonata lease with only 44,000 miles my wife is so scared to driving Hyundai anymore. We talk to the dealer they don’t give us loaner car still one week from now they are telling us to pay $13,000 for the repair. | Crash: No Fire: No | Unknown |
| Sep 2023 | UNKNOWN OR OTHER | The car slowly goes forward after releasing the break | Crash: No Fire: No | Unknown |
| Aug 2023 | POWER TRAIN | The contact owns a 2021 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the vehicle lost motive power with the oil warning light illuminated. The contact was able to restart the vehicle; however, the failure recurred. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The contact related the failure to NHTSA Campaign Number: 22V746000 (Power Train); however, the VIN was not included in the recall. The failure mileage was approximately 41,000. | Crash: No Fire: No | 41,000 |
| Aug 2023 | SEAT BELTS | 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. | Crash: No Fire: No | 26,450 |
| Jul 2023 | ELECTRICAL SYSTEM | So for the past year and half my cars left turn signal has been working intermittently. It just stops working and then it starts again. I have taken it to the dealer many times they changed out signal assembly i have taken many videos show proof. I am told at the dealer if you dont bring it in when it is not working then they cannot do anything even if i have video proof documenting this issue for the past year this is a serious safety issue that must be addressed. My next step is to contact Hyundai directly hopefully you can investigate this issue. This is very dangerous. | Crash: No Fire: No | Unknown |