Ford 2009 F-250 Owner's Manual page 15

Instrument Cluster
Harley-Davidson vehicles
Warning lights and gauges can alert you to a vehicle condition that may
become serious enough to cause expensive repairs. A warning light may
illuminate when a problem exists with one of your vehicle's functions.
Many lights will illuminate when you start your vehicle to make sure the
bulbs work. If any light remains on after starting the vehicle, refer to the
respective system warning light description for additional information.
Note: Some warning lights are reconfigurable telltale (RTT) indicator
lights and will illuminate in the Message Center Display and function the
same as the warning light.
Service engine soon: The Service
engine soon indicator light
illuminates when the ignition is first
turned to the on position to check
the bulb and to indicate whether the vehicle is ready for
Inspection/Maintenance (I/M) testing. Normally, the "Service engine
soon" light will stay on until the engine is cranked, then turn itself off if
no malfunctions are present. However, if after 15 seconds the "Service
engine soon" light blinks eight times, it means that the vehicle is not
ready for I/M testing. See the Readiness for Inspection/Maintenance
(I/M) testing in the Maintenance and Specifications chapter.
Solid illumination after the engine is started indicates the On Board
Diagnostics System (OBD-II) has detected a malfunction. Refer to On
board diagnostics (OBD-II) in the Maintenance and Specifications
15
2009 F-250/350/450/550 (f23)
Owners Guide, 2nd Printing
USA (fus)