Ford Focus wont start,fault code 15

When the PATS LED is Flashing continuously the vehicle will not start, try locking/unlocking drivers door lock with key or remote & then try ignition again Check DTCs (Diagnostic Trouble Codes) on your vehicle using flash codes PATS LED INDICATOR The LED indicator is used for the PATS system and also other Anti-theft systems fitted to the Ford vehicle range. When the ignition is switched ON, the PATS LED will illuminate for 3 seconds while it performs a self-test, after which it extuingishes. When the PATS system is armed and immobilised the vehicle, the PATS LED will flash quickly. If there is a fault on the PATS system, and the engine can start, the PATS LED will illuminate for 60 seconds continuously, and then flash the PATS fault code 10 times. If the engine is unable to start and disabled by the PATS system, then the PATS LED will FLASH for 60 seconds and then flash the PATS fault code 10 times. PATS LED is mounted either in the front headlining or next to the heater controls/clock. The PATS system has it’s own self diagnosis test procedure which flashes codes. The PATS LED will flash quickly for 1 minute, and then start flashing the fault code as follows:- Example : code 31 3 Flashes 1 Flash Three seconds delay Repeat of code for 10 times Code Descriptions :- Code 11 Transceiver not connected Code 12 Transceiver Code 13 No key data received Code 14 Part of the transponder code received Code 15 Wrong transponder key Code 21 Less than the minimum keys required programmed Code 22 Failed diesel pump control unit identification Code 23 The response code between pump control unit & powertrain LED = Always ON or OFF Check the fuse 15 (5 amp) Could try the key programming process in owners handbook and see if it fixes the problem. If not , you may need to either get a new key or have the key programmed by a garage / mobile car lock specialist .