[Mechanical Inspection]

WARNING: This page is about a different car, the 2017 Kia Niro. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition switch OFF.
Disconnect the NVLD connector.
Remove the NVLD.
Connect the hose (A) to the canister hose connected port below.
After immersing the hose (A) in water, Apply more than 6 mbar (positive) pressure to Atmosphere port (B).
If the NVLD is normal, many bubbles will indicate large leak.
NOTE: Allowable internal leakage of 0.35 g/hr at 3 mbar will show as one bubble every second (approximately).

Fig 1: Immersing Hose In Water
Courtesy of KIA MOTORS AMERICA, INC.