I just replaced the battery on an '06 FEH. Now, the red "Theft" light is lit when the engine is not running and the engine doesn't shut off at stops even after the vehicle is warmed up. My scanner is showing no DTC codes.

What could this be? I really don't want to take it to a local stealer.

 

I'm going off memory here, but it sounds like a PATS (passive anti-theft system) module problem. Have you searched the forum here, or googling for an answer already?
Here's an interesting thread:
http://www.ford-trucks.com/forums/11...tart-pats.html
Also from memory, try disconnecting the battery again for longer than 15min and reconnect. If that doesn't fix it, try locating the PATS fuse (if it has one) and disconnecting it to see if it temporarily fixes the problem. It may unfortunately be something the dealership needs to do.

 

Battery ground was off all last night. No, I haven't checked the PATS, but I will. Hard to imagine why that would allow the vehicle to run normally except for engine shut-down at stops.

 

The PATS is on a 2 amp fuse:

"Powertrain Control Module (PCM
relay), Fuel pump relay, Main fan
relay, High/Low speed fan relay 2,
PATS module"

I don't think if this fuse was blown the truck would operate.

If you have the PATS reset procedure, I'm all ears.

 

No the vehicle would not operate if the PATS was faulty. The theft light flashing with the key out of the ignition is normal. The vehicle keeps running with the key out and never turns off? How are you shutting the vehicle down then?