As I don't know the exact model of vehicle. I have supplied info for the F150 truck as most fords use the same PATS system.
Passive Anti-Theft System (PATS) communicates PCM through instrument cluster to enable or disable vehicle's engine. Within one second after engine start, PCM must receive an enable signal from instrument cluster or engine will be disabled. Along with enable signals, instrument cluster and PCM share messages that confirm security codes shared during initial installation. This shared security data makes instrument cluster and PCM a matched pair, so neither will operate in another vehicle.
When system is functioning properly and ignition switch is turned to RUN or START position, THEFT indicator light will turn on for 3 seconds, then turn off. Vehicle will be enabled to start and run. If a problem exists in PATS, THEFT indicator light will stay on or flash continuously. Go to SELF-DIAGNOSTIC SYSTEM.
TEST QD: DTC P1260
Perform this test when instructed during QUICK TEST or if directed by other test procedures. This DTC indicates that Passive Anti-Theft System (PATS) has determined a theft condition existed and engine is disabled. When activated, PATS will disable fuel system. To disarm PATS, use key or remote keyless entry to unlock door. This DTC is an indicator to check for DTCs in PATS. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT.
1) Continuous Memory DTC P1260: Check For Passive Anti-Theft System DTCs
If any Passive Anti-Theft System (PATS) DTCs are present, service PATS DTCs as necessary before continuing. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If no PATS DTCs are present, go to next step.
2) Check For Other Powertrain Control Module DTCs
Repair all other PCM DTCs before diagnosing DTC P1260. See DIAGNOSTIC TROUBLE CODE DEFINITIONS table. If no other PCM DTCs are present, go to next step.
3) Attempt To Start Engine
Clear DTCs and perform KEEP ALIVE RANDOM ACCESS MEMORY RESET PROCEDURE under CLEARING CODES. Attempt to start engine. If engine does not start, DTC P1260 is not cause of no-start. Diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - CNG & GASOLINE article for engine no-start diagnosis. If engine starts, no problem is indicated at this time. Testing is complete. For intermittent no-start, or starts and stalls problem, check for intermittent PATS faults. PATS will not cause engine to stall after one second of operation. For intermittent stalls while driving, verify scan tool-to-PCM communication during problem. If PCM communication error occurs, possible causes are:
Loss Of PWRs Or GNDs To PCM
Faulty PCM PWR Relay
Faulty EEC PWR Diode
Shorted VREF Signal
Repair as necessary. Return vehicle to customer.
Sunday, January 18th, 2009 AT 6:38 AM