GMC 2009 Sierra - Manual (Page 321)

{ CAUTION:
Fuel can spray out on you if you open the
fuel cap too quickly. If you spill fuel and then
something ignites it, you could be badly burned.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any hiss noise
to stop. Then unscrew the cap all the way.
If your vehicle is a dual fuel tank chassis cab model,
and it runs out of fuel, refuel the front fuel tank first
to ensure a quick restart.
Be careful not to spill fuel. Do not top off or overfill
the tank and wait a few seconds after you have finished
pumping before removing the nozzle. Clean fuel from
painted surfaces as soon as possible. See Washing
Your Vehicle on page 5-102.
When replacing the fuel cap, turn it clockwise until it
clicks. It will require more effort to turn the fuel cap
on the last turn as you tighten it. Make sure the cap
is fully installed. The diagnostic system can determine
if the fuel cap has been left off or improperly installed.
This would allow fuel to evaporate into the atmosphere.
See Malfunction Indicator Lamp on page 3-44.
The TIGHTEN GAS CAP message will be displayed
on the Driver Information Center (DIC) if the fuel
cap is not properly installed. See DIC Warnings and
Messages on page 3-59 for more information.
{ CAUTION:
If a fire starts while you are refueling, do not
remove the nozzle. Shut off the flow of fuel
by shutting off the pump or by notifying the
station attendant. Leave the area immediately.
Notice: If you need a new fuel cap, be sure to
get the right type. Your dealer/retailer can get
one for you. If you get the wrong type, it may not
fit properly. This may cause your malfunction
indicator lamp to light and may damage your
fuel tank and emissions system. See Malfunction
Indicator Lamp on page 3-44.
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