Chevrolet 2009 Aveo Owner's Manual page 218

When replacing the fuel cap, turn it clockwise until it
clicks. 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 3-32.
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.
5-10
Notice: If a new fuel cap is needed, be sure to get
the right type. Your dealer/retailer can get one
for you. The wrong type might not fit properly. This
can cause the malfunction indicator lamp to light
and can damage the fuel tank and emissions
system. See Malfunction Indicator Lamp on
page 3-32.