This page covers 3 recalls, 65 owner complaints and EPA fuel economy for the 2018 Kia Niro.
49 mpg combined
4.8 L/100km
Small Station Wagons
Fuel economy data from fueleconomy.gov (EPA / U.S. Dept. of Energy). Annual cost based on 15,000 mi/yr at 55% city driving and current fuel prices. MPG is U.S. gallons; L/100km converted.
Powertrain complaints dominate what 2018 Kia Niro owners report, making up roughly a third of all filed complaints for this model year. The most common pattern involves transmission response failures, owners describe shifting into reverse or drive and getting no movement, with the vehicle only recovering after being shut off and restarted, sometimes not at all. A smaller but consistent cluster of engine complaints includes oil pressure concerns, with owners reporting the oil warning light activating during normal driving. Electrical system issues round out the top three, and owners describe a range of intermittent problems: turn signals cutting in and out, power windows that stop responding for extended periods, and exterior lighting such as fog lights and headlights cycling on and off before failing more persistently.
65
Total Complaints
5
Crash-Related
3
With Injuries
By System
The 2018 Kia Niro has 3 recalls, all carrying fire risk: one from transmission fluid leaking onto an internal circuit board, and one from an electrical relay overheating the rear seats.
The transmission issue involves fluid finding its way onto the printed circuit board inside the hydraulic clutch actuator, which can cause a fire in the engine compartment. On the hybrid system side, a main relay inside the power relay assembly can develop poor electrical connections that build heat, which transfers upward into the rear seating area and raises the risk of fire from below the cabin. Prior repair attempts on the relay issue did not fully resolve it, which is why a follow-up recall was issued. Both fire risks affect hybrid models; the transmission recall also extends to plug-in hybrid variants of this vehicle.
At a glance
What can fail
Fluid may leak into the circuit board inside the hydraulic clutch actuator, potentially causing an engine compartment fire.
What the fix does
Dealers will inspect and replace the hydraulic clutch actuator if needed and install a new fuse at no cost.
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Complaints are owner-reported and reflect individual experiences, not confirmed defects. They are distinct from recalls. Data sourced from the national vehicle safety complaint database. See trending complaints →
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The Main Relay in the Power Relay Assembly may have weak electrical connections, causing increased resistance and overheating of the rear seats.
What the fix does
Dealers will inspect the Power Relay Assembly and replace it or the Main Relay as needed, at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The Main Relay in the Power Relay Assembly may have loose or corroded electrical connections that increase resistance and can cause electrical faults.
What the fix does
Dealers will inspect the Power Relay Assembly for damage. If undamaged, the Main Relay will be replaced; if damaged, the entire assembly will be replaced.
Summarized — see the official notice for exact wording, dates, and contacts.
