With a smart key, you can lock or unlock a door (and tailgate) and even start the engine without inserting the key.
The functions of the buttons on a smart key are similar to the remote keyless entry. (Refer to the “Remote keyless entry” in this chapter.)
Carrying the smart key, you may lock and unlock the vehicle doors (and tailgate). Also, you may start the engine. Refer to the following, for more details.
Kia Niro 2017 (DE HEV) Service Manual: Front Seat Shield Inner Cover Components and components location
Component Location
1. Front seat shield inner cover
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Kia Niro 2017 (DE HEV) Service Manual: Auxiliary 12V Battery Repair procedures
Removal
Auxiliary 12V Battery
1.
Open the trunk.
2.
Remove the luggage side trim [RH] side cover (A).
3.
Turn the ignition switch OFF and disconnect the battery negative (-)
terminal (A).
...