Malfunction Indicator Lamp (MIL)
WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
The MIL informs the driver of a malfunction in the powertrain that affects the vehicle emissions system. The MIL is illuminated when a fault condition is detected by the powertrain control module (PCM) and a diagnostic trouble code (DTC) has been set. The instrument cluster receives the MIL data from the PCM over the high speed CAN.