535 problems have been reported for the 2018 Hyundai Sonata. The following chart shows the 24 most common problems for 2018 Hyundai Sonata. The number one most common problem is related to the vehicle's engine and engine cooling with 213 problems. The second most common problem is related to the vehicle's electrical system (62 problems).
In our research we use the PPMY index to compare the reliability of vehicles. The PPMY index of a certain model is defined as the problems reported per thousand vehicles per Year. The total sales of the 2018 Hyundai Sonata in the United States are 129,653 units [1]. If the total number of problems reported by Hyundai Sonata owners in the last 8 years is 535, and the age of the vehicle is 8, the PPMY index can then be calculated as
PPMY Index = 535 / 129,653 / 8 * 1000 = 0.52.
For more information, refer to this page: A study of reliability comparison across Hyundai Sonata model year vehicles.
The following chart shows the number of problems reported during each of the service years since the debut of the 2018 Hyundai Sonata in 2018.
| Service Year | Number of Problems |
|---|---|
| 2026 | |
| 2025 | |
| 2024 | |
| 2023 | |
| 2022 | |
| 2021 | |
| 2020 | |
| 2019 | |
| 2018 |
When making the decision between buying a new or used Hyundai Sonata, the following table can be used to compare the 2018 Hyundai Sonata with the Hyundai Sonata from other model years. Note that the number of problems reported for the 2018 Sonata is 535 while the average number of problems reported for the 30 model years of the Hyundai Sonata is 729.