Most common 2018 Kia Niro problems
Share of the 60 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Kia Niro complaints by model year
Best Niro years: 2021. Years to avoid: 2023, 2025, 2022. Compare all years →
2018 Kia Niro recalls (3)
Power train › Automatic transmission › Internal › Clutches/bands › Actuators/solenoids
Kia America, Inc. (Kia) is recalling certain 2017-2022 Niro and 2018-2022 Niro Plug-in Hybrid vehicles. Fluid may leak into the printed circuit board inside the hydraulic clutch actuator, which can result in an engine compartment fire.
Remedy: Dealers will inspect and replace the hydraulic clutch actuator as necessary and install a new fuse, free of charge. Owner notification letters were mailed December 29, 2023.
Hybrid propulsion system
Kia Motors America (Kia) is recalling certain 2017-2018 Kia Niro hybrid electric vehicles previously recalled under recall 18V-666. The Main Relay within the Power Relay Assembly (PRA) may have inadequate connections between its contacts, causing increased electrical resistance, which can overheat the rear seats.
Remedy: Dealers will inspect the PRA and replace either the PRA or the Main Relay, as necessary, free of charge. Owner notification letters were mailed January 9, 2023. Owners may contact Kia customer service at 1-800-333-4542.
Hybrid propulsion system
Kia Motors America (Kia) is recalling certain 2017-2018 Kia Niro hybrid electric vehicles. The Main Relay within the Power Relay Assembly (PRA) may have inadequate connections between its contacts, causing increased electrical resistance.
Remedy: Kia will notify owners, and dealers will inspect the Power Relay Assembly (PRA) for damage. If no damage is found, the main relay will be replaced. If damage is found, the PRA will be replaced.
NHTSA defect investigations
Federal safety investigators have looked into a possible defect involving the 2018 Kia Niro:
Pedestrian alert sounds
NHTSA received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at NHTSA.gov under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles.
What 2018 Kia Niro owners say
Transmission & drivetrain
The contact owns a 2018 Kia Niro. The contact stated that when the vehicle was shifted into reverse(R), the vehicle failed to respond. The vehicle was turned off and restarted to reset the transmission, but the vehicle failed to respond while in reverse(R). The vehicle was shifted to drive(D) but failed to respond. The vehicle was shifted into park(P). The vehicle was towed to a local dealer. The dealer diagnosed the vehicle and determined that the transmission fuse and the hydraulic clutch actuator had failed and that the transmission needed to be replaced. The contact researched online and related the failure to NHTSA Campaign Number: 23V534000 (Power Train). The manufacturer was contacted and the contact was informed that the VIN was not included in the recall. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 175,000.
The contact owns a 2018 Kia Niro. The contact stated that the vehicle failed to restart. The hybrid system warning was illuminated. The vehicle was towed to the dealer, where the vehicle was diagnosed, but the cause of the failure could not be determined. The vehicle was then towed to a second dealer, Elgin Kia (909 E Chicago St, Elgin, IL 60120), where the cause of the failure could not be determined. The vehicle was not repaired. The contact received notification of NHTSA Campaign Number: 23V534000 (Power Train); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not notified of the failure. The failure mileage was approximately 91,000. VIN tool confirms parts not available.
Engine & cooling
The contact owns a 2018 Kia Niro. The contact stated while driving at an undisclosed speed, the engine revved up. The contact stated that the accelerator pedal was depressed; however, the vehicle was slow to respond. Eventually, the vehicle shifted into gear and started to move. The contact stated that the check HEV and turn off engine error messages were displayed. The vehicle was taken to the local dealer, where it was diagnosed that a faulty engine clutch activator needed to be replaced. The mechanic informed the contact that the vehicle was not covered under a recall. The vehicle was not repaired. The contact stated that the failure was related to NHTSA Campaign Number: 23V534000 (Power Train). The manufacturer was not contacted. The failure mileage was approximately 120,000.
The contact owns a 2018 Kia Niro. The contact stated while driving approximately 65 MPH, the vehicle started shaking and vibrating abnormally. The contact stated that the accelerator pedal was depressed; however, the vehicle failed to respond as needed. The contact stated that the message "Engine Overheating - Request Service Now" and "Engine Control System" was displayed. The contact had taken the vehicle to an independent mechanic where it was diagnosed and determined that coolant had intruded into the engine block and the engine needed to be replaced. The vehicle had not been repaired. The contact attempted to contact the manufacturer but was unable to reach a Representative. The failure mileage was approximately 74,000.
Electrical system
The contact owns a 2018 Kia Niro. The contact stated that occasionally driving at various speeds, the vehicle hesitated to stop as intended while the brake pedal was depressed, and the brake pedal was depressed to the floorboard. The message "Stop - Regenerative Braking Failure" was displayed. The contact restarted the vehicle as a temporary repair; however, the failure reoccurred. The vehicle was taken to a local dealer, where it was diagnosed, and a 91400 fuse Kit was installed, and various repairs were performed. The vehicle was repaired out-of-pocket; however, approximately one month later, the failure reoccurred. The vehicle was taken back to the same local dealer where it was diagnosed; however, the cause of the failure was not determined. The vehicle was not repaired. The contact stated that the vehicle was taken back to the same local dealer, where it remained. …
On 2/15/2022 around 10:00AM, I was driving my vehicle as normal. Noticed brake lights ahead, I was about 3 car lengths back, which I always try to drive since I am on the road a lot and I prefer not to have an accident. Well this time, I put my foot on the brake as normal and the vehicle felt like brakes were not even working, pushed harder with my foot and waited for that pumping feeling (which I have felt before) and literally nothing! Once I was about a car lengths away, I knew my vehicle was not stopping so I sat up straight and leaned back before the air bags deployed in my face. I have since come home and found several complaints from other 2018 Kia Niro owners that have made a complaint about this on other forums and with the NHTSA and Carcomplaints.com - This issue has been ignored by Kia about braking system.
2018 Kia Niro engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 1.6L 4-cyl hybrid | 6-speed dual-clutch | FWD | 52 / 49 / 50 |
| 1.6L 4-cyl plug-in hybrid | 6-speed dual-clutch | FWD | 48 / 44 / 46 |
EPA ratings. Class: Wagon.
Frequently asked questions
Is the 2018 Kia Niro a good car?
There isn't enough complaint history for the Niro to compare model years reliably. So far owners have filed 60 complaints with NHTSA.
What is the most common problem with the 2018 Kia Niro?
The transmission & drivetrain — 19 complaints, 32% of all complaints for this model year. Next are the engine & cooling (18) and electrical system (18).
How many recalls does the 2018 Kia Niro have?
There are 3 recalls for the 2018 Kia Niro, the most recent from July 31, 2023 (actuators/solenoids). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Kia Niro?
The best years by complaints, compared at the same age, are 2021. Years to avoid or approach with caution: 2023, 2025 and 2022. See the full Kia Niro years comparison.
At what mileage do 2018 Kia Niro problems happen?
The median mileage reported in complaints is about 40,000 miles; 60% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.