Kia has downgraded the official range for the all-electric e-Niro due to a testing error.

Autocar reports that the organization overseeing the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) cycle provided an incorrect testing methodology and approved the results it generated while testing the Kia e-Niro. Due to this error, the e-Niro was tested for a disproportionate length of time on the WLTP urban cycle and at slower overall speeds.

This reduced the energy needed and created an over-estimation of the crossover’s range. Kia discovered the error while carrying out testing for one of its future electric vehicles.

Despite the changes, the Kia e-Niro still has impressive range figures.

Initially, the range-topping Kia e-Niro with its 64 kWh battery was rated at 301 miles (474 km) on a single charge while the more-affordable 39.2 kWh e-Niro was rated at 193 miles (310 km). These figures have since been revised to 282 miles (453 km) and 179 miles (288 km) respectively.

The South Korean automaker says it has started to contact owners of the e-Niro to inform them of the error.

Despite the revisions to the e-Niro’s quoted range, the crossover still utilizes a number of advanced technologies to maximize efficiency. For example, it includes regenerative brakes and an Eco Driving Assistant System which tells the driver how to drive more efficiently. This system also includes Coasting Guide Control (CGC) and Predictive Energy Control (PEC).

Powering the long-distance 64 kWh Kia e-Niro is an electric motor delivering 201 hp and 291 lb-ft (395 Nm) of torque. Meanwhile, the 39.2 kWh model is driven by a 134 hp electric motor.