How the 2021 compares
One of the better Sonata years
Owners filed about 82% fewer complaints than a typical Sonata year. The area owners reported most is the engine and cooling, which half of owners reported by about 46,000 miles.
Based on owner complaints to NHTSA, compared with other Sonata years from 2012 to 2024. A good year can still be a bad car, so check the one you are looking at.
Owners have filed 135 complaints with NHTSA about the 2021 Hyundai Sonata. The most reported problem area is the engine and cooling (35, 26% of complaints), followed by the fuel system and the transmission and drivetrain. That ranks 10th of 13 Sonata years from 2012 to 2024 for complaints. It has 4 recalls.
Complaints135filed with NHTSA
Recalls4for this model year
Crashes713 injuries reported
Fires0reported in complaints
2 of these complaints came from Utah owners.
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Start my car searchMost reported problems
Problem areas ranked by how many complaints mention them. One complaint can name more than one area. Open an area to see what to check on a 2021 Hyundai Sonata before you buy.
Engine and cooling
35 complaintsStalling, misfires, oil consumption, leaks, overheating and engine failure.What to check before you buy
Half of the owners who gave a mileage had the problem by about 46,000 miles.
What to check before you buy
- Ask the seller not to warm the car up, and start it cold. Listen for ticking, knocking or a rough idle in the first minute.
- Pull the oil dipstick and the oil cap. Low oil, a gasoline smell or a milky film on the cap are reasons to walk away or get an inspection.
- Plug in an OBD2 scanner. Stored or pending codes matter, and so do readiness monitors that show "not ready", which usually means the codes were cleared right before the sale.
- Ask for oil change records. A gap in the records on a model known for engine complaints is a negotiating point at minimum.
Tools that help
What owners said
The Exhaust Heat Recovery System (EHRS) has failed for the second time on this vehicle. The first failure occurred at approximately 35,000 miles and was repaired under Hyundai Technical Service Bulletin 23-EM-009H, which Hyundai issued to address this exact defect across 2020-2023 Sonata Hybrid models. The vehicle has now reached 71,000…Owner complaint, filed 2026
Hyundai technical service bulletin 23-EM-009H (EHRS COOLANT LEAK) - AKA a faulty heat exchange that causes the coolant to leak into the exhaust and burn away. Resulting in a very hard to diagnose coolant disappearance. This should be a recall. They have literally already acknowledged a manufacturer defect with the service bulletin. The…Owner complaint, filed 2026
Fuel system
34 complaintsHesitation, stalling, fuel smell, fuel pump and injector failures.What to check before you buy
Half of the owners who gave a mileage had the problem by about 75,000 miles.
What to check before you buy
- Smell around the engine bay and under the rear of the car for raw fuel.
- On the test drive, accelerate firmly from a stop and up a grade. Stumbling, surging or a flashing check engine light are red flags.
- Fuel pump recalls are common. Check this exact VIN for open recalls before you buy.
Tools that help
What owners said
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…Owner complaint, filed 2026
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…Owner complaint, filed 2026, at 100,000 miles
Transmission and drivetrain
25 complaintsHarsh or delayed shifts, slipping, shuddering, CVT whine, and drivetrain clunks.What to check before you buy
Half of the owners who gave a mileage had the problem by about 22,000 miles.
What to check before you buy
- Drive it from cold if you can. Shifts should be smooth in every gear, including reverse.
- Feel for slipping (revs rise without the car speeding up), shudder at low speed and a delay when you put it in gear.
- Listen for whining, which is a common CVT complaint, and clunks when you go from drive to reverse.
- If it has 4WD or AWD, engage it on the test drive and ask when the transmission and differential fluids were last changed.
Tools that help
What owners said
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…Owner complaint, filed 2026
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.…Owner complaint, filed 2026
Electrical system
18 complaintsDead batteries, warning lights, failed screens and cameras, and electrical shorts.What to check before you buy
What to check before you buy
- Test every switch: windows, locks, mirrors, seat heaters, the screen, the backup camera, Bluetooth and every USB port.
- Watch the dash at startup. Every warning light should come on briefly and then go out.
- Have the battery and charging system tested. A weak alternator or battery drain shows up here.
Tools that help
What owners said
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.…Owner complaint, filed 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.Owner complaint, filed 2026
Lights, wipers and visibility
12 complaintsHeadlights that dim or fail, wiper and washer failures, and windshield cracks.What to check before you buy
What to check before you buy
- Check every light: headlights on low and high, fog lights, brake lights, turn signals and reverse lights.
- Run the wipers on every speed with washer fluid, and run the defroster front and back.
Tools that help
What owners said
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…Owner complaint, filed 2023, at 13,300 miles
*The front sunroof panel exploded toward while the car was running, but in the driveway in park. *Our safety was compromised by the shattered tempered glass falling into the car. *The problem was noted at the dealer, who stated they had not seen this happen before and believed it to be from a rock chip. *The roof has been inspected by…Owner complaint, filed 2022
Driver assist systems
10 complaintsPhantom braking, false collision warnings, and lane keeping or backup sensors that act up.What to check before you buy
What to check before you buy
- Where it is safe, try the adaptive cruise and lane keeping on the test drive and watch for sudden braking or warnings with nothing there.
- Check the windshield in front of the camera and the bumper sensors for cracks, chips or poor repairs.
- Ask whether the windshield has been replaced. The camera has to be recalibrated afterward, and many shops skip it.
Tools that help
What owners said
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…Owner complaint, filed 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…Owner complaint, filed 2026
Brakes and stability control
4 complaintsBrakes that feel soft or grab, grinding, ABS and stability control faults.What to check before you buy
What to check before you buy
- The pedal should feel firm and the car should stop straight without pulling, grinding or a pulsing pedal.
- The ABS and stability control lights should go out after startup and stay out.
- Look through the wheels at the rotors. A deep lip on the edge means brakes are due soon, which is a fair thing to negotiate on.
Tools that help
What owners said
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.…Owner complaint, filed 2026, at 42,000 miles
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…Owner complaint, filed 2025
Air bags
4 complaintsAir bag warning lights, air bags that did not deploy, and inflator recalls.What to check before you buy
What to check before you buy
- The air bag (SRS) light should come on at startup and go out within a few seconds. If it stays on, the system may not work in a crash.
- Air bag recalls are some of the most serious. Check this exact VIN for open recalls and get proof any recall work was done.
Tools that help
What owners said
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…Owner complaint, filed 2022
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.Owner complaint, filed 2025
Seats and seat belts
4 complaintsBelts that will not latch or retract, seat adjusters and passenger occupancy sensors.What to check before you buy
What to check before you buy
- Pull out and latch every seat belt, and let each one retract on its own.
- Try every seat adjuster, and watch for a passenger air bag "off" light when an adult is in the seat.
Tools that help
What owners said
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…Owner complaint, filed 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…Owner complaint, filed 2023, at 26,450 miles
Body, doors and structure
4 complaintsRust, doors and liftgates that will not latch, leaks, and frame or structure concerns.What to check before you buy
What to check before you buy
- Look underneath with a flashlight. Utah road salt is hard on frames, brake lines and the bottoms of doors.
- Open and close every door, the hood and the liftgate, and lock and unlock each one.
- Use a paint thickness gauge and compare panels. A panel that reads very differently from the rest has likely been repaired.
Tools that help
What owners said
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.Owner complaint, filed 2023
• 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.…Owner complaint, filed 2026
Steering
2 complaintsLoss of power steering assist, wandering, play in the wheel and noises when turning.What to check before you buy
What to check before you buy
- Turn the wheel lock to lock while parked and listen for groaning, clicking or binding.
- On a straight road the car should track straight with the wheel centered and no loose feeling.
- A power steering warning on the dash, even briefly, deserves a mechanic’s look before you buy.
Tools that help
What owners said
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…Owner complaint, filed 2023
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…Owner complaint, filed 2022
Cruise control and acceleration
2 complaintsHesitation, loss of power, sudden acceleration and cruise control problems.What to check before you buy
What to check before you buy
- On the test drive, press the gas gently and firmly. The response should be smooth with no lag or surge.
- Set the cruise control, then use resume and cancel to make sure each one works.
Tools that help
What owners said
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.…Owner complaint, filed 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…Owner complaint, filed 2022
Suspension
1 complaintClunks over bumps, broken springs, worn struts and uneven tire wear.What to check before you buy
What to check before you buy
- Drive over a few bumps and potholes slowly with the radio off and listen for clunks or rattles.
- Check the tires for uneven wear on the inside or outside edges, a sign of alignment or suspension trouble.
- Look behind the wheels for oily, wet shocks or struts.
Tools that help
What owners said
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…Owner complaint, filed 2026
Hyundai Sonata complaints by year
Compare the 2021 with other years before you choose one. Tap a year to see its problems.
Compare with similar 2021 midsize cars
Each car is rated against its own other years, since popular models always get more complaints than rare ones.
| Car | Vs. its other years | Recalls |
|---|---|---|
| 2021 Hyundai Sonata | One of the better years | 4 |
| 2021 Toyota Camry | One of the better years | 1 |
| 2021 Honda Accord | One of the better years | 4 |
| 2021 Nissan Altima | One of the better years | 2 |
2021 Hyundai Sonata recalls
This is every recall issued for the 2021 Hyundai Sonata, not what is still open on one car. A recall that was fixed does not show up any differently here. Check a VIN at NHTSA to see what is still open on the car you are looking at, and ask the seller for proof any recall work was done.
Fuel system
- Risk
- A melted fuel tank can leak, increasing the risk of a fire.
- Fix
- Dealers will inspect and replace the check valve.
Full recall summary
Hyundai Motor America (Hyundai) is recalling certain 2020-2023 Sonata vehicles. A damaged check valve can allow air to enter the fuel tank, causing it to expand and contact hot exhaust components, melting the tank.
Transmission and drivetrain
- Risk
- Loss of drive power increases the risk of a crash.
- Fix
- Dealers will inspect and replace the transmission, as necessary.
Full recall summary
Hyundai Motor Company (Hyundai) is recalling certain 2021-2022 Santa Fe, Sonata, Veloster N, 2022 Santa Cruz, Elantra N, and Kona N vehicles. The vehicle's "fail-safe" limited-mobility drive mode may be impaired, when prompted by a transmission oil pump malfunction, which can result in a complete loss of drive power.
Windows, mirrors and wipers Windshield
- Risk
- A windshield that detaches from a vehicle during a crash can increase the risk of injury.
- Fix
- Dealers will remove and reinstall the front windshield panel, free of charge.
Full recall summary
Hyundai Motor America (Hyundai) is recalling certain 2020-2021 Santa Fe, 2021 Sonata, and Elantra vehicles. During manufacturing, the windshield may not have been properly bonded to the vehicle, allowing it to detach in a crash.
Fuel system
- Risk
- A fuel leak increases the risk of a fire.
- Fix
- Dealers will inspect and tighten, or replace the fuel pipe as necessary, free of charge.
Full recall summary
Hyundai Motor America (Hyundai) is recalling certain 2021-2022 Santa Fe and Sonata vehicles equipped with 2.5L turbocharged engines. Fuel may leak at the pipe connection between the high-pressure fuel pump and fuel rail.
2021 Hyundai Sonata questions
What are the most common problems with the 2021 Hyundai Sonata?
The most reported problem areas on the 2021 Hyundai Sonata are the engine and cooling (35 complaints), the fuel system (34 complaints) and the transmission and drivetrain (25 complaints).
Is the 2021 Hyundai Sonata a good year to buy?
One of the better Sonata years. Owners filed about 82% fewer complaints than a typical Sonata year. The area owners reported most is the engine and cooling, which half of owners reported by about 46,000 miles. Based on owner complaints to NHTSA, compared with other Sonata years from 2012 to 2024. A good year can still be a bad car, so check the one you are looking at.
How many recalls does the 2021 Hyundai Sonata have?
NHTSA lists 4 recalls for the 2021 Hyundai Sonata. The most recent, from Nov 2025, covers the fuel system. Recalls cover the whole model year, so check the VIN of the car you are looking at to see which are still open.
At what mileage do 2021 Hyundai Sonata problems start?
Half of the owners who reported a problem with the engine and cooling gave a mileage of about 46,000 miles or less. Half of the owners who reported a problem with the fuel system gave a mileage of about 75,000 miles or less. Plenty of cars have these problems later or never, so ask for service records.
Which Hyundai Sonata years should I avoid?
The Sonata years with the most complaints compared with the rest are 2012 and 2013. Years with clearly fewer complaints are 2019, 2020 and 2021. Years from 2022 on are too new to rate fairly yet.
Check the exact car
These problems are for the model year as a whole. Here is how to find out about the one you are looking at.
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Where these numbers come from. Complaints are reports that owners filed with the National Highway Traffic Safety Administration (NHTSA), counted from NHTSA’s complaint database as of November 5, 2026. Owners do not have to prove a problem to file one, so a complaint is a report, not a confirmed defect. Models that sell in big numbers get more complaints, and newer model years have had less time on the road, so compare years of the same model rather than different models. Recalls come from NHTSA’s recall database and cover every vehicle of that model year, not one particular car. Quotes are trimmed, and anything that looks like a VIN is hidden.
- Check a specific car for open recalls at NHTSA
- Decode a VIN to see recalls, safety ratings and complaints for that exact year, make and model