Owners have reported 8 crashes and 14 injuries to NHTSA for the 2021 Hyundai Sonata. These are unverified owner reports, not confirmed defect rates.
Owner complaints34
ELECTRICAL SYSTEM
Owners report frequent issues with the 12-volt battery in the 2021 Hyundai Sonata, particularly in hybrid models. Complaints frequently mention the battery dying unexpectedly, often requiring manual intervention to reset or jump-start the vehicle. This issue is noted across various mileage ranges, with some reports emerging as early as 59,850 miles. Additionally, multiple owners describe problems with the car shutting off while driving, which poses safety risks. There are also mentions of electrical failures affecting door locks and windows, with some reports of burning smells and potential fire hazards. These patterns suggest potential reliability concerns for prospective buyers, especially regarding the vehicle's electrical system.
Owner complaints29
UNKNOWN OR OTHER
Owners of the 2021 Hyundai Sonata frequently report issues related to electrical system malfunctions, with multiple complaints about dashboard warning lights activating simultaneously, leading to a loss of acceleration. Transmission and drivetrain problems are also noted, with some owners experiencing difficulty shifting gears or unexpected power loss. HVAC system failures, such as a broken component preventing proper defrosting, are reported as well. Safety implications include two reported crashes and five injuries, with incidents involving unintended acceleration and automatic emergency braking activation. Mileage and timelines vary, but several issues are noted shortly after purchase or within the first year of ownership. These patterns suggest potential safety risks and repair challenges for prospective buyers considering a used 2021 Sonata.
Severity signals: 2 crash, 0 fire, 5 injury reports
Owner complaints26
ENGINE
Owners of the 2021 Hyundai Sonata frequently report engine-related issues, with many experiencing sudden loss of power and engine stalling. Common symptoms include engine misfires, knocking noises, overheating, and oil leaks, often leading to the engine seizing or failing to restart. These problems typically occur at various mileages, with some incidents reported as early as 5,600 miles. Safety concerns are evident, with one crash reported and multiple instances of vehicles stalling on highways, creating potential hazards. Buyers should be aware of these issues, especially since some owners report lengthy repair times and difficulties with warranty coverage.
Severity signals: 1 crash, 0 fire, 0 injury reports
Owner complaints22
POWER TRAIN
Owners of the 2021 Hyundai Sonata frequently report issues related to the vehicle's power train, specifically with the transmission and coolant system. Common symptoms include loss of power, failure to accelerate, and erratic RPM behavior, often without warning lights or error codes. Transmission problems are reported around 2,700 to 44,000 miles, with some owners experiencing multiple transmission replacements or repairs. Coolant issues are noted with sudden loss of coolant and overheating, sometimes leading to white exhaust smoke. Safety implications include potential loss of control due to power loss and overheating, which could pose risks during driving. Buyers considering this model should be aware of these recurring issues and their potential impact on vehicle reliability.
Owner complaints6
FUEL/PROPULSION SYSTEM
Owners of the 2021 Hyundai Sonata frequently report issues related to the fuel/propulsion system, particularly concerning a strong gasoline smell that persists despite dealership visits. Some owners mention unresolved fuel system issues linked to a recall, with one being advised to replace the fuel assembly at their own expense. Complaints also describe erratic vehicle behavior, such as unexpected acceleration and deceleration, especially when the vehicle is at low fuel levels or in park. These issues typically arise at low mileages, around or below 11,000 miles. Safety implications are noted, with owners expressing concerns about potential fire hazards and feeling unsafe due to the unpredictable vehicle operation.
Owner complaints4
AIR BAGS
Owners of the 2021 Hyundai Sonata report issues with the air bag system, particularly involving non-deployment during collisions. In two cases involving crashes, the air bags did not deploy, resulting in one incident with seven injuries. One owner notes that the air bag sensors may be positioned ineffectively, potentially affecting deployment during certain types of impacts. Another complaint highlights the air bag system's occupant classification system (OCS), which fails to activate the passenger air bag for a small adult using a seat cushion. These reports suggest potential safety risks, especially in crash scenarios, and are relevant for prospective buyers assessing the vehicle's safety features.
Severity signals: 2 crash, 0 fire, 7 injury reports
Owner complaints3
ENGINE AND ENGINE COOLING
Owners of the 2021 Hyundai Sonata report issues related to engine and engine cooling, with common symptoms including gasoline odor from the engine, engine overheating, and oil plug failure. Complaints frequently mention abnormal gasoline consumption and engine overheating alerts, typically occurring around 32,000 to 87,000 miles. One report describes a significant oil leak due to an oil plug backing out, resulting in a complete loss of engine oil and potential safety risks while driving in mountainous areas. These issues suggest potential safety implications, such as the risk of engine seizure during operation, which may be of concern to prospective buyers.
Owner complaints2
SEAT BELTS
Owners of the 2021 Hyundai Sonata report issues with seat belts, primarily involving failure to release and secure properly. One complaint describes a seat belt that tightens and locks, preventing adjustment or removal, leading to the belt being cut to free the passenger. Another owner notes a problem where the driver-side seat belt requires two clicks to secure properly. These issues are reported at approximately 26,450 miles. While no crashes or injuries are noted, the inability to adjust or secure seat belts may pose a safety risk.
Owner complaints2
SERVICE BRAKES
Owners of the 2021 Hyundai Sonata report issues with the braking system, including unexpected ABS activation and brake pedal lockup. One owner describes the ABS engaging without cause while reversing and again at highway speeds, leading to temporary loss of control. Another owner experienced a brake pedal that would not depress, resulting in a crash, with the automatic brake sensor failing to activate. These complaints indicate potential safety risks, particularly during highway driving or when sudden braking is required. The issues appear to occur without a specific mileage range, as one owner notes no previous problems before the incident.
Severity signals: 1 crash, 0 fire, 0 injury reports
Owner complaints2
STEERING
Owners report issues with the 2021 Hyundai Sonata's steering, with multiple complaints describing a loss of power steering and difficulty in moving the steering wheel. Common symptoms include all dashboard warning lights activating, the battery discharge warning light coming on, and a complete deactivation of safety features such as Forward Collision Warning and Lane Departure Warning. These issues typically arise within the first year of ownership and around 9,200 miles, according to the complaints. Safety implications are significant, as the loss of power steering and deactivation of safety systems could lead to a loss of vehicle control. These patterns suggest potential electrical issues that remain unresolved despite multiple dealer inspections.
