Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter magnetic switch for potential freezing and, if necessary, replace the starter magnetic switch (solenoid) assembly.
full bulletin at NHTSA ↗2021 Hyundai Sonata electrical problems
moderate Owners of the 2021 Hyundai Sonata have filed 14 NHTSA complaints about the electrical at roughly $850 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See electrical across all vehicles →
Complaints
14
Recalls
0
Avg fix
$850
| Model year | electrical complaints |
|---|---|
| 2017 Sonata | 46 |
| 2018 Sonata | 51 |
| 2019 Sonata | 11 |
| 2020 Sonata | 26 |
| 2021 Sonata (this page) | 14 |
| 2022 Sonata | 12 |
| 2023 Sonata | 8 |
| 2024 Sonata | 14 |
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering electrical on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin provides information related to the changes introduced in the 2025 1st Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system as described in this TSB.
full bulletin at NHTSA ↗This bulletin provides information related to the changes introduced in the 2024 2nd Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system. Refer to the 2024 2nd Navigation Map and Software Update Improvements section in this TSB for a list of specific changes. The software can be downloaded via Navigation Updater (NAU) and updated by USB. The NAU website is https://update.hyundai.com/US/EN/navigationUpdate. For certain models equipped with a relevant Bluelink package, the software may be downloaded and applied via OTA update.
full bulletin at NHTSA ↗Some vehicles may exhibit a loss of connectivity or interruptions in the middle of using Bluelink Service functions. This may be due to an irregular disconnection on Verizon’s communication network. Follow the procedure in this TSB to reestablish the connection via the AVN pinhole reset method.
full bulletin at NHTSA ↗Certain Sonata (DN8) and Sonata (DN8A) vehicles may experience issues with the air conditioning due to damaged wiring in the engine room junction box. This bulletin provides instructions to replace the multi-fuse, reroute the damaged wiring using the blower wiring kit, and replace the fuse label.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
2021 Sonata owners report a cluster of electrical faults that have proven difficult to remedy even after repeated dealership visits. The most serious pattern involves idle surge—one owner made nine trips to the dealer over three months for an uncontrolled RPM jump to 1,300 that causes the car to lurch forward at red lights. EGR valve replacement, PCM replacement, and multiple re-learns have all failed to stick; the problem returns within days each time.
Wiring harness failures appear across multiple subsystems. One owner experienced a burning smell under the dashboard that escalated to a fire hazard condition; repair parts have been on order from Korea for six months with Hyundai aware that hundreds of customers are waiting. Another owner's 2020 Sonata has a cracked blower harness on backorder for three months, and the 2021 is developing the same issue.
Fuse box receptacles are melting and causing AC blower failure; one owner reports visible burn marks and a fire hazard, with repair delayed indefinitely due to parts backlog. Battery issues plague hybrid models—auxiliary 12V batteries drain to dead within an hour of normal driving. Engine stalling without fault codes, intermittent turn signals despite assembly replacement, and door-lock button failures that require workarounds are reported by multiple owners. Dealers frequently cannot reproduce issues or blame external causes (rodent deterrents) when problems persist.
Same Hyundai Sonata electrical reports on nearby years: 2018 · 2019 · 2020 · 2022
Failure modes owners describe
Idle RPM Surging & Unintended Forward Motion
Engine RPM jumps to approximately 1,300 at idle, causing the vehicle to surge forward at stops without driver input on the accelerator. Owner reports keeping foot on brake to prevent rear-end collision. Condition persists after multiple dealer visits (9 times) and multiple repairs including EGR valve replacement, PCM replacement, and system re-learning.
When: 59,850 miles; started July 1, warranty expires at 60,000 miles; occurred intermittently over three-month period
Symptoms owners cite: RPM jumps to 1,300 at idle/red lights; Vehicle surges forward without accelerator input; Vehicle maintains 30 mph cruise without accelerator pedal; Condition resolves temporarily after restart but returns within days; Persists after multiple service attempts
Repairs/costs cited: EGR valve replaced; PCM (computer) replaced; system re-learned multiple times by dealer—condition recurred in all cases
Recalls/TSBs owners mention: Dealer performed 9 service visits; owner notes this is the same issue reported for same model year in July 2022
Fuse Box Receptacle Burnout & AC Blower Motor Failure
Fuse box receptacle where the AC blower motor fuse seats shows visible burn marks and melting, causing intermittent blower motor failure. Loose connections between fuse and receptacle result in erratic on/off cycling during drive. Owner reports fire hazard concern due to burnt/melting condition. Issue first appeared post-November 2023 repair (initial blown fuse), then recurred July 2024.
When: Post-November 2023; failed again July 2024; dropped for repair 9/3/2024
Symptoms owners cite: AC blower motor stops working intermittently; Blower turns on/off randomly while driving; Visible burn marks and melting in fuse box receptacle; Loose fuse-to-receptacle connection
Repairs/costs cited: Blown fuse replaced November 2023 (without notification of receptacle damage); receptacle/fuse box repair pending at dealership (expected delay over one month)
Wiring Harness Burning & AC Blower Motor Failure
Engine compartment wiring harness failure causes burning smell under dashboard and loss of AC function. Owner reports smell escalated to fire hazard level during drive to dealership. Harness repair requires parts from Korea and has been pending for six months. Owner states Hyundai is aware of the problem and multiple customers (reported as 100s) are waiting for replacement parts.
When: June 2024
Symptoms owners cite: Burning smell under dashboard, worsening during drive; Air conditioner stops working; Risk of vehicle fire per owner report
Repairs/costs cited: Wiring harness replacement required; parts on order from Korea for six months
Recalls/TSBs owners mention: Owner advised multiple customers awaiting parts; Hyundai aware of issue per service advisor
Wiring Harness Cracked & Blower Motor Inoperative
Cracked wiring harness in blower motor circuit prevents AC function. This failure mode appears across multiple model years (2020 and 2021). One owner reports same issue on both 2020 and 2021 Sonatas, with 2020 harness on backorder for three months and blower inoperative through summer.
When: 2020 and 2021 model years; backorder delays three months or more
Symptoms owners cite: Blower motor stops working; No AC cooling available; Vehicle becomes uncomfortably hot
Repairs/costs cited: Wiring harness replacement required; parts on backorder (three months reported)
12-Volt Auxiliary Battery Rapid Discharge & Fire Hazard
Auxiliary 12V lithium battery (on hybrid model) discharges completely within 60 minutes after 60-mile drive cycles, occurring repeatedly. Owner attributes potential fire hazard from lithium battery failure and parked vehicle next to house. Dealer blamed aftermarket rodent deterrent, but issue persists after deterrent disabled. Battery resets nearly daily. Still under 10-year/100,000-mile warranty.
When: Occurred 6 times in 6 weeks; current status under warranty repair
Symptoms owners cite: 12V auxiliary battery dead within 60 minutes of 60-mile drive; Lithium battery fire hazard concern; Battery resets nearly daily; Vehicle sits dormant for days between uses
Repairs/costs cited: Dealer performed cursory check and blamed rodent deterrent; owner disabled deterrent without resolving issue
Recalls/TSBs owners mention: Vehicle covered under 10-year/100,000-mile bumper-to-bumper warranty
12-Volt Battery Random Discharge (Hybrid Models)
12V battery discharges randomly on 2021 Hyundai Sonata Hybrid. Owner reports finding online posts of identical failures on same model year. Vehicle currently at dealership pending warranty claim confirmation.
When: Recent; hybrid model
Symptoms owners cite: 12V battery dies randomly; Pattern seen across multiple 2021 Sonata Hybrid owners
Recalls/TSBs owners mention: Warranty claim pending confirmation
Stalling & Loss of Electrical Power While Driving
Vehicle shuts off and loses all electrical power while driving on highway on at least two separate occasions. Owner pulled safely to roadside both times. Vehicle restarts immediately each time, runs normal afterward. Dealership mechanical scan found no faults. Battery tested normal. Owner reports Hyundai denies addressing the issue.
When: Two incidents reported; second occurred the day before complaint submission
Symptoms owners cite: Complete engine shutdown while highway driving; Total loss of electrical power; Immediate restart successful; No codes or faults detected on scan
Repairs/costs cited: Scan performed; battery tested—no problems found
Recalls/TSBs owners mention: Hyundai denies addressing issue
Engine Stall While Driving (Non-Hybrid)
Car shut itself off while driving on five separate occasions. After first two incidents, vehicle went to dealership where no fault was found and battery replacement was recommended. New battery installed by dealer, but car stalled three more times within two weeks of replacement. Vehicle restarts immediately each time. Owner cites serious safety risk.
When: Five separate incidents reported; three after battery replacement
Symptoms owners cite: Engine shuts off while driving; Immediate restart successful; No fault codes found after replacement battery installed
Repairs/costs cited: Battery replaced by dealership; stalling continued post-replacement
Door Lock & Window Button Intermittent Failure
Power door lock buttons and rear window buttons become unresponsive unless driver repeatedly opens and closes vehicle door. After using the button once following this workaround, buttons become unresponsive again, requiring process to repeat. Owner reports this is unsafe especially when vehicle is in motion.
When: Ongoing issue
Symptoms owners cite: Door lock buttons unresponsive; Rear window buttons unresponsive; Requires repeated door open/close cycle to temporarily restore function; Buttons fail again after single use
Intermittent Left Turn Signal Failure
Left turn signal stops working intermittently, cycling on and off unpredictably. Owner has documented failures on video over one-year-plus period, taken vehicle to dealer multiple times, and signal assembly has been replaced, yet issue persists. Dealer states they cannot diagnose without the malfunction occurring during service, despite video evidence. Owner cites serious safety issue.
When: Over one-year-plus; ongoing
Symptoms owners cite: Left turn signal works intermittently; Stops working for extended periods; Restarts without warning; Continues after turn signal assembly replacement
Repairs/costs cited: Turn signal assembly replaced; issue persists
Infotainment & HVAC System Electrical Malfunction
Infotainment system will not switch to radio mode with no AM/FM or satellite signal. Simultaneously, HVAC blower stopped functioning—no defrost, heat, or AC. Blower motor itself tested and operates normally; blower motor resistor has been replaced. Technicians indicate root cause is an electrical connection issue within the system.
When: Timing not specified
Symptoms owners cite: Infotainment radio mode inoperative; No AM/FM signal; No satellite signal; HVAC blower non-functional; Defrost inoperative; Heat and AC non-functional
Repairs/costs cited: Blower motor resistor replaced; blower motor tested and confirmed working
Synthesized from 14 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
In June 2024, I was driving my vehicle when I started to smell burning from under the dashboard. As I continued to drive, the smell got worse, and on my way to the dealer, my air conditioner stopped working. I took my car back to the dealer for service, and several days later, I was told that my car needed a hardness connected to several components in the engine compartment. I remember while I…
This car has two problems. 2 weeks I was driving on the highway. All the sudden the shutoff and lost all power on the car. Thank god I pulled to the side of the road safely. Turned the car off and turned it back on. The car started to run normal. I took it to mechanic. They scanned the car with their computer. Said the car has no problems. Tested the battery and all other components. No problems…
My 2021 Hyundai Sonata Limited Hybrid 12v battery has started to die randomly. My car is currently with the Hyundai dealer to confirm if this will be a warranty claim. Searching online, I have found other posts of people complaining about a similar issue with their 2021 Hyundai Sonata Hybrid.
Had electrical trouble with your 2021 Hyundai Sonata?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the electrical problem on the 2021 Hyundai Sonata?
It's a documented issue but not catastrophic. 14 complaints have been filed. Repairs average $850 and most owners catch it before it causes a breakdown.
At what mileage does the electrical typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $850 for electrical repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to electrical?
No active recalls currently cover electrical issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Hyundai/Sonata.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.