2015 Kia Optima power train problems
49 owner complaints filed with NHTSA name the power train on the 2015 Kia Optima — 5% of all complaints for this model year.
What owners report
“P1326 code flashing engine light knock sensor went out 3 times in 6 months and just replaced it again and this time engine light didn't go off I was reading that there was a recall on this but apparently mine doesn't state it. Car cannot pass emissions if engine light is on and the 15th of June is…”
filed Jun 8, 2026
“On December 27, 2025, at approximately 150,556 miles, my 2015 Kia Optima Hybrid experienced sudden engine knocking, power loss, and failure while driving at 65 mph on a highway. The vehicle dropped into limp mode and I had to pull off the highway. The car required towing to the dealership as it…”
filed Feb 13, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area…
TSB_TRA046_R5 · Service Bulletin/Repair Instructions · issued Apr 17, 2025This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced.
TSB_TRA046_R4 · Service Bulletin/Repair Instructions · issued May 16, 2024
Power Train problems in other Optima years
| Year | Reports | Share |
|---|---|---|
| 2020 Optima | 25 | 18% |
| 2019 Optima | 16 | 8% |
| 2018 Optima | 18 | 8% |
| 2017 Optima | 20 | 8% |
| 2016 Optima | 72 | 10% |
| 2014 Optima | 20 | 3% |
| 2013 Optima | 64 | 5% |
| 2012 Optima | 54 | 6% |
| 2011 Optima | 25 | 4% |
| 2010 Optima | 24 | 32% |
| 2009 Optima | 33 | 28% |
| 2008 Optima | 18 | 13% |
Other reported problem areas on the 2015 Kia Optima
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.