The SMART mode may be limited in following situations. (The OFF indicator illuminates in those situations.)
Hyundai Sonata LF 2014-2019 Service Manual: Description and Operation
Description
The starting system includes the battery, starter, solenoid
switch, ignition switch, inhibitor switch (A/T), clutch pedal switch
(M/T), ignition lock switch, connection wires and the battery cable.
When the ignition key is turned to the start position, current flows and energizes ...
Hyundai Sonata LF 2014-2019 Owners Manual: Checking the Engine Coolant Level
WARNING
Never remove the radiator cap or the drain plug while the engine and radiator
are hot. Hot coolant and steam may blow out under pressure, causing serious injury.
Turn the engine off and wait until the engine cools down. Use extreme care
when removing the radiator cap. Wrap a thick towel ...