Things To Do:

Review Service Procedures and Technical Service Bulletins (TSBs) for latest information.
Disconnect the diagnostic tool for 20 seconds before cycling ignition to OFF, ACC, or RUN.
When replacing ignition keys, make sure the owner throws out ALL old keys.
Disconnect battery cables when replacing PATS module, ICM, VIC, HEC, SCIL, PCM, or EEC.
Look for fault codes in PATS. The PATS function will store fault codes when the PCM records a P1260.
Be certain of the vehicle model year. Use only parts and keys specified for the appropriate model year.
Check to make sure the issue is not with multiple PATS keys, small electronic devices that can be used to purchase gasoline, or other items on same key ring.
Check to ensure vehicle does not have an aftermarket remote starter. Disable any Remote Starter equipment, especially anything nearby the PATS Transceiver. Ford FCSD Dealer installed Remote Starter systems are approved for use in Ford vehicles.
Check to ensure vehicle does not have an aftermarket engine immobilizer. The Ford FCSD aftermarket remote entry system comes with a starter interrupt that should be disabled on PATS equipped vehicles.
If the Alarm sounds when the ignition is turned to RUN or START, refer to the appropriate PERIMETER ALARM article.