I have a 1999 F150 4x4 that has a theft device warning light that flashes very quickly when I try to start the truck in outside temps of 85 or above and will not start. My mechanic is stumped. If the light is flashing fast, it will turn over but will not start. The mechanic replaced the transceiver module, but no luck. The truck starts fine at 85 degrees and under. I live in a humid area. Would appreciate any help, am considering changing vehicles due to this continuous problem. Thanks for any suggestions.

 

I am normnally reluctant to do so, but I'm going to suggest that you use a Ford dealership for this problem. Try to find one that has a technician who really understands the PATS system to prevent "parts swapping" at your expense. Insist on talking to the tech in person. Do not rely on the service advisor to correctly communicate all your info.

The PATS system has the antenna ring around the ignition cylinder. The antenna connects to the PATS transceiver under the dash which then connects to the electronic instrument cluster. The cluster then communicates PATS status to the PCM (via the internal (SCP) network bus) which, if PATS fails, will disable the engine (cranks but won't start). Quite a complex system that, if you don't have access to the sub-networks, that is difficult to diagnose (properly).

Good luck.

Steve

 

Hmm...I should check that out. Mine is an '05 and I noticed when it's warm out it doesn't start properly. We've had high 90s low 100s temps here lately and on two occasions I was unable to start the truck, not sure if it actually has to do with the heat though. I never noticed the light on the dash.

 

I took the truck into our local dealership, the problem was a diode, costs were minimal, took care of the cruise control recall while there as well, thanks for your suggestion.

 

Steve,

I am marking this one in my day timer. I don't think I have ever seen you suggest this for a fix.

Good thing too, trying to diagnose that didoe might have created a longer thread then Brad doing his power slider install.

Steve