GMC 2009 Sierra - Manual (Page 187)

Fuel Gage
When the ignition is on, the fuel gage tells you about
how much fuel you have left in your tank.
The gage will first indicate empty before you are out
of fuel, and you should get more fuel as soon as
possible.
Here are some situations you may experience with your
fuel gage. None of these indicate a problem with the
fuel gage.
• At the gas station, the fuel pump shuts off before
the gage reads full.
• It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may
have indicated the tank was half full, but it actually
took a little more or less than half the tank’s
capacity to fill the tank.
• The gage goes back to empty when you turn off
the ignition.
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