This warning light indicates the fuel tank is nearly empty. When it comes on, you should add fuel as soon as possible. Driving with the fuel level warning light on or with the fuel level below “E” can cause the engine to misfire and damage the catalytic converter.
Hyundai Tucson (LM) 2010-2015 Service Manual: Variable Intake Solenoid (VIS) Valve Repair procedures
Inspection
1.
Turn the ignition switch OFF.
2.
Disconnect the VIS valve connector.
3.
Measure resistance between VIS valve terminals 1 and 2.
Specification: Refer to "Specification"
Removal
1.
Turn the ignition switch OFF and disconnect the battery negative (-) cable.
2.
...
Hyundai Tucson (LM) 2010-2015 Service Manual: Description and Operation
Description
System Overview
The System offers the following features:
-
Human machine interface through a 1-stage button, for terminal switching and engine start.
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Control of external relays for ACC / IGN1 / IGN2 terminal switching and STARTER, without use of mechanical ignition switch ...