Check Fuel Cap Indicator
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The check fuel cap indicator is used to indicate significant leaks in the fuel tank evaporative system due to a loose fuel cap. The fuel tank pressure is monitored by the PCM and if a leak is detected it signals a fault to the instrument cluster over the communication network. Once the PCM has detected a loose fuel cap and the indicator is illuminated, the indicator (Escape, Mariner) or a display in the message center (Hybrid) remains illuminated until the fuel cap is secured and the ignition switch is cycled one time.