2021 Hyundai Sonata Problems: 2 Issues Every Owner Should Know
2021 model year · 940+ owner reports · Updated April 2026
According to Au7o's analysis of 940+ owner reports, the 2021 Hyundai Sonata has 2 documented known issues. No issues are rated critical, indicating generally reliable ownership. The most commonly reported issue is Infotainment System Freezing/Issues with 520 owner reports. Across all issues, repair costs range from $0 to $800. DIY maintenance guides at au7o.io.
All 2 Known Issues
On the 2015-2021 Hyundai Sonata, the infotainment system can freeze, become unresponsive, or experience connectivity issues. Bluetooth pairing problems, navigation crashes, and touchscreen lag are common complaints.
Common Symptoms
- Touchscreen freezes
- Bluetooth won't connect
- Navigation crashes
- Slow response to inputs
- Random reboots
How to Fix
Update infotainment software. Perform system reset. Delete paired Bluetooth devices and re-pair. If persistent, head unit may need replacement. Check for Hyundai service campaigns.
What Owners Are Using
Parts and tips from 520+ owners who fixed this issue
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
- TipSearch Hyundai Sonata forums and owner groups for real-world experiences and DIY guides
- TipGet multiple quotes from independent mechanics - dealer prices can be 2-3x higher for the same repair
- UpgradeProfessional OBD-II diagnostic scanner for reading infotainment and body module codes (BlueDriver Bluetooth Pro OBD2 Scan Tool)
On the 2015-2021 Hyundai Sonata, some Sonata owners experience unexplained battery drain, resulting in a dead battery after sitting for several days. Various electronic modules may not go to sleep properly. The smart key system can also contribute to drain.
Common Symptoms
- Dead battery after sitting
- Battery won't hold charge
- Need frequent jump starts
- Key fob battery dies quickly
- Electronics act erratically
How to Fix
Have dealer perform parasitic draw test to identify culprit. Common causes include smart key module, BCM, or telematics. Ensure latest software updates installed. Use battery maintainer for vehicles that sit.
What Owners Are Using
Parts and tips from 420+ owners who fixed this issue
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
- TipSearch Hyundai Sonata forums and owner groups for real-world experiences and DIY guides
- TipGet multiple quotes from independent mechanics - dealer prices can be 2-3x higher for the same repair
- UpgradeHigh-performance AGM battery with excellent cold cranking amps and deep cycle capability (Optima RedTop AGM Battery)
- UpgradeOEM-quality replacement battery with reliable performance (ACDelco Professional AGM Battery)
- UpgradeAutomatic battery maintainer to prevent parasitic drain issues during storage (Battery Tender Junior 12V Battery Charger Maintainer)
- UpgradeAutomotive relay replacement set for common relay failures (Bosch Automotive Relay 5-Pin 12V)
- UpgradeDigital multimeter for diagnosing fuse, relay, and module electrical faults (Innova Digital Multimeter)