Which parts fail
Components named in complaints (battery, alternator, wiring, ignition, instrument cluster, infotainment).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2018 Hyundai Sonata owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2018 Hyundai Sonata. The contact stated that while driving approximately 60 MPH the vehicle suddenly began sputtering and then completely stalled. The contact had to coast to the side of the road and noticed the check engine light illuminated. After approximately 10 minutes, the vehicle was able to restart. When starting the vehicle there would be a sputtering followed by the vehicle shutting off. The failure began to occur while idle as well. The contact stated that while attempting to reverse out of a parking spot the vehicle suddenly accelerated forward instead. As a result, the vehicle ended up crashing into a concrete light post. The air bags did not deploy. There were no injuries or medical attention needed. The vehicle was able to be driven after. No police report was filed. …
The contact owned a 2018 Hyundai Sonata. The contact stated that upon her daughter reaching her destination, she observed brown smoke emanating from the engine compartment. Within a short while, the vehicle became completely engulfed in flames, prompting a bystander to attempt to extinguish the fire with a fire extinguisher, but was unsuccessful. Local emergency services arrived and were able to extinguish the flames. A fire report was filed, and it was indicated that the fire may have been electrical, but an exact cause had not been determined. A police report was filed, and no injuries were reported. The vehicle was towed to a tow yard and deemed a total loss by the contact's insurance provider. The manufacturer was not notified of the failure. The failure mileage was 125,000.
Vehicle 1 operating normally in traffic on [redacted] in Westfield MA. Operator 1 notices alert on dashboard. As Operator 1 looks down briefly and returns eyes immediately to the road, she sees Vehicle 2 braking to slow or stop. Operator 1 depresses brakes, but vehicle does not slow as it usually does, nor does Automatic Emergency Braking engage as it always has in the past. Front of Vehicle 1 makes contact with rear of Vehicle 2. Dashcam footage appears like brakes did not activate at all, either manually or automatically. Vehicle 1 airbags deploy. Westfield Police respond, as well as Westfield Fire, who cut the battery cable. Vehicle towed to Interstate Towing, Inc. Yard 5, 20 Clifton St, Westfield, Ma 01085. [phone] interstatetowing.com. …
Unknown what system failed. The vehicle is at an impound lot and can be inspected on request. Police and fire department were on the scene. Police did provide a report # , and fire department provided a fire rescue case number. Safety of driver was put at risk due to the fire and potential for burning or even death. Other drivers could have been at risk if traffic had not allowed for quick movement to side of the road. No warning lamps had been on prior to the drive and none prior to fire. First indication was a burning smell while driving. As pulling over, another driver honked to alert to fire he could see from rear of ca,. before I noticed the flames. Upon getting out of car first flames I saw appeared to be coming from under passenger side of car. The fire department arrived about 15 minutes after pulling to side of the road. The car was fully engulfed in flames. …
The vehicle had safety and mechanical problems shortly after purchase, even with low mileage. The issues included warning lights, abnormal noises, repeated mechanical failures, and poor performance that affected the safe operation of the vehicle. These problems started early and continued over time despite repairs and maintenance. Before the incident, the vehicle showed signs of malfunction, including instability while driving and loss of normal performance. These symptoms created an unsafe driving condition and increased the risk of a crash. I believe the vehicle had defects from the beginning that affected safety. The failure contributed to the accident that occurred while driving on the highway, putting my life and my family at risk.
The contact owns a 2018 Hyundai Sonata. The contact stated that the vehicle failed to start in cold weather, below 50 degrees Fahrenheit. The contact stated that the vehicle would start as needed whenever the weather was warmer. The vehicle was taken to an independent mechanic, where it was diagnosed; however, the cause of the failure could not be determined. The dealer was notified of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 72,000.
The contact owns a 2018 Hyundai Sonata. The contact stated the trunk failed to open while using the key fob and the controllers on the interior of the vehicle. The contact had taken the vehicle to the dealer where it was diagnosed that the trunk latch had failed, and the emergency cable associated with the trunk needed to be replaced. The vehicle had not been repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was 44,176.
Odometer Fraud. The contact purchased a 2018 Hyundai Sonata. The contact discovered a mileage discrepancy while searching the vehicle history report. The contact stated that the odometer indicated several readings. The vehicle was a dealer sale. The contact was unaware that at the time of purchase, the vehicle mileage was 148,000. The contact stated that the mileage on the Title was blank, and the mileage on the registration was 75,519.
During the drive, check engine lights on then suddenly, HEV warning lights with turn off the engine with critical alert sound. I was drove again after attempting to start several times then again & again... It freaked me out when I drove on the highway, and yet to fixed & afraid to go to the dealer becase of cost & uncertain reasons. This could be big accidents on the highway.
We were heading to Lakewood NJ from Bucks County (North of Philly) . Car trouble w/ hybrid system on Rt 1, just past I-95. Got off @ Fairless Hills & took back roads. We could only go 20-30 mph. IDK how many times I pulled over. Several lights on, including "Check hybrid system. Turn Engine off", engine light, low tire pressure, battery & 3 other unidentifiable lights. I turned around to try to make it home, as 2 years ago, I had a similar issue, which turned out to be the hybrid water pump failed. We finally stopped near a park & called AAA & towed to dealer. Prior to driving, we had no fluid on our driveway. My last synthetic oil change was April 19, 2023 @ 49,097mile. I now have about 57,000 miles. Today, dealer said no oil in the car & oil pan was all wet. They claim the oil filer was loose. Why would it take 8 months to loosen to lose oil? …
Electrical complaints in other Sonata years
Frequently asked questions
How common are electrical problems on the 2018 Hyundai Sonata?
NHTSA has 60 complaints about the electrical system of the 2018 Hyundai Sonata, 16% of the model year's 374 complaints. The component named most often is wiring (1 mentions).
Is there a recall for 2018 Hyundai Sonata electrical problems?
No. NHTSA lists no electrical system recall for the 2018 Hyundai Sonata, though it has 1 recall for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2018 Hyundai Sonata electrical problems start?
Half of the complaints with a recorded mileage happened before about 22,000 miles, and 58% before 25,000 miles.
Is it dangerous?
Owners linked 3 crashes, 4 fires and 2 injuries to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.