Table 1 shows one common engine and engine cooling related problems of the 2021 Hyundai Sonata Hybrid.
| Problem Category | Number of Problems |
|---|---|
| Engine And Engine Cooling problems |
The vehicle experiences sudden, complete electrical power loss while driving at speed on highways and city streets or on the parking. All digital displays turn off, the engine shuts down, and power-assisted steering and braking are instantly lost without prior warning, presenting an extreme collision risk. The issue first occurred in August 2025 at approximately 48,000 miles and was taken to an authorized Hyundai dealer in michigan for warranty repair. The dealer held the vehicle for over 30 days but failed to correct the defect. The identical power failure has continued and recently escalated to daily occurrences. A second Hyundai dealer (pacifico Hyundai, philadelphia, PA) diagnosed an intermittent open circuit in the engine wiring harness but Hyundai motor America refuses to repair the vehicle under warranty, claiming 'outside influence' without providing evidence. Driving a hybrid vehicle that randomly cuts all power in live traffic is a life-threatening safety hazard. Hyundai motor America has failed to rectify this critical safety defect.
See attached document for complaint.