Ford 2002 Crown Victoria Manual page 11

Light turns on solid:
Temporary malfunctions may cause your light to illuminate. Examples
are:
1. The vehicle has run out of fuel.
2. Poor fuel quality or water in the fuel.
3. The fuel cap may not have been properly installed and securely
tightened.
These temporary malfunctions can be corrected by filling the fuel tank
with high quality fuel of the recommended octane and/or properly
installing and securely tightening the fuel cap. After three driving cycles
without these or any other temporary malfunctions present, the light
should turn off. (A driving cycle consists of a cold engine startup
followed by mixed city/highway driving.) No additional vehicle service is
required.
If the light remains on, have your vehicle serviced at the first available
opportunity.
Light is blinking:
Engine misfire is occurring which could damage your catalytic converter.
You should drive in a moderate fashion (avoid heavy acceleration and
deceleration) and have your vehicle serviced at the first available
opportunity.
Under engine misfire conditions, excessive exhaust temperatures
could damage the catalytic converter, the fuel system, interior
floor coverings or other vehicle components, possibly causing a fire.
Check fuel cap
Illuminates when the fuel cap is not
installed correctly. Check the fuel
cap for proper installation. When
the fuel filler cap is properly
re-installed, the light(s) will turn off
after a period of normal driving. Continuing to operate the vehicle with
the check fuel cap light on, or a mis-installed fuel cap can activate the
Service Engine Soon/Check Engine warning light.
It may take a long period of time for the system to detect an
improperly installed fuel filler cap.
For more information, refer to Fuel filler cap in the Maintenance and
specifications chapter.
Instrument Cluster
CHECK
FUEL
CAP
11