2021 Hyundai Sonata Reliability Score & Common Problems

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.

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.

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.

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.

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.

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.

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.