2001 Light Truck Vehicle Manual

Incomplete vehicles produced by Ford Motor Company, in some instances, are equipped with Optional Prep Packages. These include the Ambulance Prep, School Bus Prep, Motorhome Prep, Shuttle Bus Prep and Commuter Van Packages. The completed vehicle type charts on page 5 will identify incomplete vehicles and the optional prep packages or trim codes that may be required by Ford if final stage manufacturers wish to rely on the Statements of Conformity or, in some cases, preserve the Ford new vehicle warranty.

https://www.fleet.ford.com/truckbbas/non-html/2001/IVMLtTrk.pdf