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Ironmike, Ford Technician
Category: Ford
Satisfied Customers: 3385
Experience:  30 years ASE Master tech L1 . Ford master
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1999 Ford Expedition XLT: V8..the flashing theft light?Wont start

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1999 Ford Expedition XLT Triton V8 - 4.6
How do you reset the flashing theft light?
Won't start...


If you have another ignition key try it. If you have the key fob/remote you can next try to lock and unlock the vehicle and then start. This system cannot be disabled. The anti theft works with the PCM and if the right signal is not received it will not enable to start. It would be best to check for codes if a scanner is available. Most parts stores scan for free but they only use minimum function scanners. If the anti theft light is flashing there is a system fault, it should go on with the key on and then go off after a few seconds.

let me know what happens

Customer: replied 5 years ago.
No other key

Have a 5 Digit keyless entry code, used that and tried to turn it over and still will not turn over and the flashing

Theft light is still going...
If you have a key that failed or the PATS receiver has failed you will need to get it repaired at a shop than can program the key. In most cases the dealership will be the only one with access to the vehicles security system with a diagnostic tool. Key fobs can be programmed without the diagnostic tool but not ignition keys. If you use the key or key less entry it disables the perimeter system. There are really 2 systems on this vehicle.
Customer: replied 5 years ago.
the key did not fail.. the key goes into the lock in the door and works fine.
the iginition key did not fail, the key goes into the ingition swith fine cranks but wont turn over
Believe it is because of the flashing theft light. am certified worked with firestone 20+ years and this one has me stumped...

key has a transponder, if it does not send a signal or the receiver does not get one or send one to the pcm the vehicle will not start.

dealership IDS scanner gives the tech a big advantage

Ironmike and other Ford Specialists are ready to help you
Customer: replied 5 years ago.
Is this a common problem with these vehicles? Have you delt with this before?
yes. It can be several causes like I said, the cluster can even be at fault. First the tech would look for trouble codes, then communication between the modules. You can check fuses , always a good place to start.