2020 Kia Optima Transmission Problems

Owner reports

Selected complaints filed with NHTSA by 2020 Kia Optima owners, lightly cleaned up (personal details are redacted by NHTSA).

I am filing this complaint due to severe and ongoing safety defects in my 2020 Kia Optima EX, which has repeatedly stalled while driving, creating a life-threatening road hazard. Since September 2024, my vehicle has suffered from major failures, including a complete transmission replacement, multiple high-pressure fuel pump replacements, multiple oil flushes due to fuel contamination, and all fuel injectors replaced. Despite all of these "repairs" performed by a Kia-authorized dealership, the check engine light continues to return, and the vehicle still stalls unexpectedly, making it dangerous to drive. On March 10, 2025, after Kia claimed to have tested the vehicle for 200 miles, I picked up the car from the dealership, only for it to stall and trigger the check engine light within hours before I even reached my destination. …

The vehicle experiences a dual-clutch transmission shudder in low gears and at low speeds. This issue causes a sudden loss of speed in situations such as merging onto a highway, leaving a parking spot, or while driving at approximately 30 mph. The shudder occurs randomly and poses a serious safety concern. The problem first appeared in 2020 when the vehicle had fewer than 5,000 miles on it. Beginning in 2024, at around 20,000 miles, the condition began escalating rapidly, with the shudder occurring more frequently and with greater severity. All incidents have been recorded on dash cam and provided to the dealership's service department. The vehicle has been serviced multiple times for this issue and was kept at the dealership for approximately six weeks in total. Despite this, the dealer refuses to acknowledge the problem, citing the absence of warning lights. …

The vehicles 7-speed dual clutch transmission (DCT), is horribly jerky at very low speeds and on take off. It has become dangerous to drive as my wife almost caused an accident from the vehicle not reacting to acceleration pedal, or from it reacting completely unexpectedly. The transmission is very jerky as you take the foot off the brake without pressing accelerator pedal, it shakes the entire vehicle. It also jerks heavily if you barely touch the gas pedal on take off. Dealership has done a software update on the transmission which only helped initially for about 2-3 weeks, after which the transmission started behaving in that way much worse. It is a constant and persistent issue, however, as there are no fault codes or check engine light is not displayed, the dealer states there is nothing they can do to fix the problem. …

My 2020 Kia Optima had engine failure and engine is being replaced now. I've had this car for 1yr/84k miles. It went limp on the freeway 2 mos ago and I could've caused an accident when it shut down. Would not go over 30 mps, engine light kept blinking and had knocking sound. Diagnostic code as the other recalls, Engine is same for the other recalls 2.4 Theta, oil was black and almost empty & just had oil changeI called kia corporate and they told me that they are not covering it since its not a recall. I have extended warranty but CNA National Warranty will only approve a used engine and a new one I would have to pay $3,000! I have made 2 car payments for a car that is immobile, $200+ for deductible, and $600+ for car service, this is not right at all. How can I get Kia to correct this. I do not want this car or any other kia! …

While driving to work, my 2020 Kia Optima suddenly lost engine power and went into limp mode in the middle of the highway, leaving me stranded and creating a severe safety hazard in traffic. The check engine light immediately started flashing and displaying diagnostic code P1326 which indicates an abnormal engine and/or a catastrophic rod bearing failure. This problem has been confirmed by the Kia dealership along with a 3rd party auto repair shop. However, Kia is refusing to cover the inspection, diagnostic, or any repairs due to the vehicle not having any open recalls, having more than 100k miles and the model of my vehicle despite this being a well known and documented manufacturing defect issue to these engines. The vehicle is currently available for inspection.

This is my 3rd or 4th complaint on here with NO RESPONSE, HELP, OR ACKNOWLEDGEMENT! My 2020 finally got engine put in and car does not drive the same. Steering wheel acts weird, the engine has a sound, the anti collision lights went off twice, but could be due to weather. Kia told me that it's my responsibility since my yr is not on recall. I'm surrendering this car asap to give me piece of mind before another engine is due. I met several people at kia that are on their 2nd and 3rd engine and the mechanics told me they know I will be back for another engine! This is wrong and now I'm out of alot of money and surrendering this will add more negative factors. I have my receipts but im not posting publicly

While driving, my 2020 Kia Optima suddenly lost engine power and went into limp mode on the road, leaving me stranded and creating a severe safety hazard in traffic. The vehicle threw diagnostic trouble code P1326, which indicates a catastrophic rod bearing failure. The problem has been confirmed by a Kia dealership scanner. However, both the dealership and Kia America are refusing to cover the inspection and repair under their safety campaigns or goodwill due to the vehicle having 180,000 miles, despite this being a well-documented manufacturing defect inherent to these engines. Prior to the failure, the check engine light started flashing. The vehicle is currently available for inspection.

On July 4th 2023, I was driving with my son in car, when unexpectedly the check engine light came on and car lost power. We were on a highway with a 65mph speed limit. I was able to pull over to side of road. Car did Start back up, however was missing and misfiring. Shaking especially under acceleration. My engine has been consuming oil for many thousands of miles, it is documented; however only an oil consumption test was performed. Hyuandai and Kia has serious engine issues and they know it. This could've been worse. Luckily I still had some brake pressure to get off the road. With this stalling on the highway, it is very dangerous.

2020 Kia Optima LX 2.4, LESS THAN 100,000 miles on car. Car started over consuming oil 2 quarts/1,000 miles. Cranked engine yesterday to go to work and serious knocking sounds, engine is rattling severely. Losing revving power, undriveable. Smoke coming out of exhaust that smells like rotten eggs. Will be taking this to get codes run but I believe this is due to Theta II engine failure issue reported in similar cars with the same engine. KIA NEEDS TO COVER THE 2020 OPTIMA UNDER LIFETIME WARRANTY PROTECTION otherwise this is a $10,000 cost to replace engine.

At gas, the vehicle jumps/judders as if it's not getting enough gas to get up and go, and then at higher speeds it goes fine. Was reported to Horne Kia while under warranty. They never found the issues. Months later issue was found by a new mechanic, now the vehicle is no longer under warranty and the TRA codes are posted online. [redacted] Reported August 2021 [redacted] Reported December 2020

Transmission complaints in other Optima years