Midsize sedans · model years 2021 to 2023
Kia K5 vs Hyundai Sonata: problems and reliability
On the 7 measures below that do not grow with sales, the Sonata looks better on 2 and the K5 on 1, with 4 too close to call.
Newest report Sep 23, 2026 · checked Sep 27, 2026
Scorecard
| Measure, 2021 to 2023 | K5 | Sonata |
|---|---|---|
| Complaints that report a crash | 7.2% | 6.4% |
| Complaints that report a fire | 1.5% | 0.3% |
| Complaints that report an injury | 6.7% | 1.6% |
| Median miles when problems are reported | 48,000 | 28,000 |
| Recall campaigns per model year | 2.3 | 1.7 |
| Do-not-drive recalls | 0 | 0 |
| NHTSA investigations | 1 | 1 |
The shaded side is lower (for miles, higher). Values within about a tenth of each other count as too close to call.
What owners complain about
The system K5 owners complain about most is fuel and propulsion; for the Sonata it is engine. Complaints citing electrical make up 19% of all K5 complaints, against 14% on the Sonata. The Sonata leans the other way on engine: 28% of its complaints, against 17% for the K5.
Kia K5Hyundai Sonata
Share of each model's complaints that cite each system, from NHTSA's own component codes. One complaint can cite several systems, so the shares add up to more than 100%.
The most reported problems
The most reported problem on the K5 is misfire (13% of its complaints). On the Sonata it is stalling (18% of its complaints), against 9.5% on the K5.
| Problem | K5 | Sonata |
|---|---|---|
| Check engine light or misfire | 13% 5476k mi | 14% 4530k mi |
| Engine stalls or loses power while driving | 9.5% 3824k mi | 18% 5522k mi |
| A/C blows warm or the compressor fails | 8.0% 3260k mi | 0 |
| Brakes grind, pulse or wear early | 6.0% 2424k mi | 1.9% 6 |
| Fuel smells, leaks, or the gauge reads wrong | 5.7% 23 | 1.6% 5 |
| Seat belt or seat problems | 5.7% 23 | 0 |
| Airbag warning light or recall | 4.7% 19 | 0 |
| Forward collision warning goes off or the camera drops out | 3.2% 13 | 0 |
Share of each model's own complaints, with the count beside it. "Most in" links to the symptom sheet for the model year with the most reports of it, and the mileage is the median from reports that gave one.
When problems start
Sonata owners report problems earlier. Half the Sonata complaints that give a mileage come before 28,000 miles; for the K5 the halfway point is 48,000. 51% of K5 reports and 69% of Sonata reports come before 50,000 miles. Older model years have had longer to reach high mileage, so a window that runs to recent years pulls both medians down.
Kia K5Hyundai Sonata
Share of the complaints that state a mileage: 98 for the K5 and 93 for the Sonata.
Worst and best years
No K5 model year stands out from the rest. The 2015 Sonata draws 3.7 times the complaints of a typical Sonata year for its age.
Kia K5Hyundai Sonata
Each bar is that model year's complaints for each year on the road, divided by the same figure for a typical year of the same model (the dashed line). Measuring each model against itself takes the sales gap between the two out of the picture, so they can share a scale. Years too new to judge are left out.
Recalls and investigations
The K5 draws more recalls: 2.3 campaigns per model year against 1.7 for the Sonata. A recall counts once however many cars it covers, so this figure does not grow with sales the way complaint totals do.
Kia K5
7 recall campaigns and 1 NHTSA investigation across these model years. Most recalled: airbags (2), fuel system (2) and lane keeping (1).
- 22V-760 (transmission and drivetrain) covers 3 model years
- 23V-149 (airbags) covers 3 model years
Investigations
- DP22003: Loss of motive power (closed)
Hyundai Sonata
5 recall campaigns and 1 NHTSA investigation across these model years. Most recalled: fuel system (2), transmission and drivetrain (2) and visibility (1).
- 25V-796 (fuel system) covers 3 model years
- 21V-524 (fuel system) covers 2 model years
Investigations
- DP22003: Loss of motive power (closed)
Whether a particular car is included depends on its VIN. Check yours at nhtsa.gov/recalls.
Crashes, fires and injuries
Crashes turn up in about the same share of complaints on both (7.2% and 6.4%). Fire reports: 6 for the K5 and 1 for the Sonata. Complaints on file report 3 deaths in the K5 and 0 in the Sonata for these model years.
Kia K5Hyundai Sonata
Share of each model's complaints in which the owner reported it. These are owners' own accounts as filed with NHTSA, and one report on its own doesn't prove a defect.
Questions
Is the Kia K5 or the Hyundai Sonata more reliable?
On the 7 measures below that do not grow with sales, the Sonata looks better on 2 and the K5 on 1, with 4 too close to call. NHTSA complaint totals cannot settle it alone: the K5 has 401 complaints and the Sonata 313 for model years 2021 to 2023, and those totals follow how many of each were sold.
Which has more recalls, the K5 or the Sonata?
The K5 has 7 recall campaigns and the Sonata 5 across model years 2021 to 2023. The K5 draws more recalls: 2.3 campaigns per model year against 1.7 for the Sonata.
What are the most common problems on the K5 and the Sonata?
The most reported problem on the K5 is misfire (13% of its complaints). On the Sonata it is stalling (18% of its complaints), against 9.5% on the K5.
More comparisons
- Hyundai Sonata vs Toyota Camry2014 to 2024
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- Kia K5 vs Toyota Camry2021 to 2026
- Kia K5 vs Honda Accord2021 to 2023