One problem related to starter solenoid has been reported for the 2018 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 Hyundai Sonata based on all problems reported for the 2018 Sonata.
Car will not start when key turned in ignition with no sound when the weather is under 30 degrees. Had it in the dealer last week and they could not find the problem. Still happening so its back in the dealer for 3 consecutive days and I cannot talk with anyone in the service department. Phone just rings then cuts off. Have done research and found other 2018 Sonata ES owners with the same problem and the solution has been the ignition starter and solenoid. When replaced the starting problem was solved. Three days now and have not heard form the Hyundai repair shop in bowie, MD. Still have my car. Such inefficiently with mechanics now days.