Within 10 seconds, and turn it to RUN .
If you only have one key or no keys at all, you use the onboard sequence. You have three alternatives:
Programming a key for a 2003 Ford F-150 involves two distinct systems: the (which allows the engine to start) and the keyless entry remote (the buttons that lock/unlock doors). The complexity of the process depends entirely on how many working keys you currently have. I. Programming the Transponder (Engine Start)