2021 Kia K5 Problems and Top Complaints – Is Your Car A Lemon?

Air bag and lighting issues are among the top complaints from vehicle owners

Updated on Author: Brian Jones

The 2021 Kia K5 replaced the Kia Optima, launched just a decade ago.

The new 2021 Kia K5 replaces the Kia Optima, launched globally just a decade ago. In a press release dated 30 June 2020, Kia says the all-new model is set to disrupt and inspire the mid-size sedan market. Built on Kia’s third-generation N3 platform, it boasts a new design identity, more turbo, more traction, and next-level technology.

In the same media release, Kia continues to call the Optima one of the auto industry’s most significant growth and achievement stories. Yet, it is no secret that sales of the Kia Optima dropped about 40% from 2015 to 2019. The most touted reason is that consumers now prefer crossovers to passenger cars. Which is why Kia stopped making the Optima and switched to producing the K5. Many people say it’s just a renamed version of the Optima!

Kia’s official explanation for reimagining the Kia Optima sedan hints at its declining popularity. “Fueled by an unstoppable spirit to push harder and work smarter, Kia was determined to give it everything instead of giving up; completely rethinking the traditional sedan.”

In an article, 2019 Kia Optima Problems and Top Complaints, Lemberg Law highlights some of the 42 complaints made to the United States Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) about this model.

There aren’t as many complaints to NHTSA about the first replacement Kia K5, the 2021 Kia K5. But 18 complaints, for what the manufacturer heralds as its “most powerful mid-size sedan ever,” are enough. Also, NHTSA is only one of many platforms for complaints.

One independent forum, Kia K5 Problems and Reliability, has 116 complaint posts, most of which have multiple responses, many with their own related complaints. These vary from a myriad of minor issues to oil leaks, start malfunctions, service brake issues, shattered sunroofs, electrical problems, and airbags failing to deploy.

Click on other model year to view more problems: 2019   2022   2023

Most Common Problems

The complaints to NHTSA are also varied, but the top complaints are about the electrical system. These are followed by complaints about the engine and airbags not deploying. These are the 3 common problems we will look at in more detail.

Additionally, there are 2 complaints each about forward-collision avoidance, lane departure issues, and the structure of the sedan. Back-over prevention, exterior lighting, the fuel/propulsion system, powertrain, seats, steering, and visibility/wipers are each linked to 1 complaint.

Between March and July 2021, Kia issued 3 recalls for the K5. These relate to airbags, the fuel system (gasoline), lane departure issues, and steering. Together they affect as many as 22,563 vehicles.

There are also 46 manufacturer communications on record for the 2021 Kia K5, 21 of which relate to the sedan’s electrical system.

2021 Kia K5 Complaint Summary

Complaint CategoryNumber of Complaints
Electrical System
Unknown Or Other
Power Train
Fuel/propulsion System
Air Bags
Service Brakes
Forward Collision Avoidance: Warnings

Electrical System Problems

The 4 complaints that relate to the electrical system are all a bit different. One kept losing its wireless “carplay” signal. On the other end of the scale, another cut-out, and smoke began to pour from under the hood. In just one minute, the car, which had only 25 miles on the clock, was destroyed by fire.

Another complaint relates to a warning light on the instrument panel. The local dealer diagnosed the problem as two faulty computer chips but didn’t fix the car. The car had about 600 miles on the clock. Kia was notified about the failure, but there is no update on the NHTSA website.

The fourth complaint relates to faulty sensors. The car was returned after almost 2 weeks, and the owner was told it was safe to drive. But, the complaint states, “I got it back with the front panel off with exposed wires and no working airbags.” Soon after this, the sensors began to malfunction again. This time, the tire pressure sensor, headlights, and speedometer were all affected.

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Air Bag Problems

The 3 complaints all involve injuries as a result of airbags not deploying.

One accident was the result of a deer jumping in front of a car traveling between 65 and 70 mph on a freeway. “Not one of the many airbags installed on this brand new car deployed. The police officer at the scene said I’m lucky to be alive.”

Another one was a frontal collision with an older car. The driver sustained neck, back, and knee injuries when the airbags didn’t deploy. Additionally, the folding seat behind the driver’s seat was dislodged. This driver says:

“Sad to say my beautiful brand new K5 that I have had for 2 months now has close to $13,000 damage. Most importantly, I am now scared to drive this thing. What if this happens again?”

The third complaint is similar to the one above. Two vehicles collided but the airbags didn’t deploy. The rear driver’s side seat unlatched itself during the collision.

Even though there is a recall that relates to airbags, the recall issue seems quite different from the experiences of the 3 NHTSA complainants. The reason for the recall is that if there is a crash, deployment of the front passenger airbag could increase the risk of injury to a child if the child is in that seat. There is no mention of airbags not deploying.

Problems with the Engine

One of the 3 engine problems is the same as the electrical system issue where the car caught fire.

Another relates to noise coming from the engine bay. The dealer found that the engine cover was off and was causing the noise. The complaint also mentions damage to the fender from rubbing the wheel/tire, and the fog light housing “hanging.”

The third complaint relates to the cooling system of the car. When the engine is turned off, antifreeze vapor escapes into the engine area. The vehicle owner noticed the problem because of a very strong smell of coolant in the garage. The “dealer has verified that the radiator cap appears to act as a vent allowing vapors to escape the system.”

What to do if your 2021 Kia K5 is a lemon? Your Lemon Rights

Not all the people who complain about problems have bought a lemon. But if it has a persistent defect that recurs and impairs the safety, use, or value of the car, it probably is a lemon.

If you suspect you do have a lemon, Lemberg Law will assess your case and advise you. We have helped to settle many lemon law car claims. Sometimes we get the car owner a replacement car, sometimes we negotiate a case settlement or a trade-in. Call our Helpline and we’ll see what we can do. Ultimately, the law makes Kia pay your legal fees.

Brian Jones

About the Author:

Brian Jones spent more than 30 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

See more posts from Brian Jones

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