Mechanics

ANTI THEFT

1999 Ford Expedition

Electrical problem
1999 Ford Expedition V8 Four Wheel Drive Automatic 135000 miles

I just replaced my blend door which required removing the dashboard, after reinstalling the dash the truck will not turn on, there is a continuous relay clicking and no acc no ignition no key remote operation, battery is good, it is like it is in anti-theft mode? All worked good before I removed the dash, I even rechecked to make sure all connections are made, I would like to know what to check first and what order to check it in, please respond
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Mrief33
July 25, 2010.




Hello. Thanks for the donation. Much appreciated

check the connections for the ignition switch. Do you have any lights showing on dash display with key ON?

Passive Anti-Theft System (PATS) vehicle protection system is designed to prevent drive-away thefts. The system is passive in that it does not require any activity from user. System uses radio frequency identification technology to verify if proper key is being used to attempt to start vehicle.
During each starting sequence, encoded ignition key is interrogated by vehicle anti-theft electronics. If key's identification code matches code programmed into anti-theft system, vehicle is capable of starting. If key's identification code is incorrect or missing, vehicle is prevented from starting.
PATS module communicates with Powertrain Control Module (PCM) through Module Communication Network (MCN). PCM then determines if engine will be enabled to start. If PCM prevents vehicle from starting because of the PATS system, PCM will store a Diagnostic Trouble Code (DTC) in memory.
PATS vehicle protection system consists of the following components: Hybrid Electronic Cluster (HEC), anti-theft (THEFT) indicator, transceiver module, encoded ignition key, MCN and Data Link Connector (DLC).
OPERATION
THEFT INDICATOR
THEFT indicator located on right side of instrument cluster is used to prove out system operation status. PATS uses THEFT indicator when ignition switch is in START or RUN position. For more information, see POWERTRAIN CONTROL MODULE (PCM).
ENCODED IGNITION KEY
When ignition switch is in START or RUN position, Hybrid Electronic Cluster (HEC) initiates encoded ignition key interrogation process. HEC supplies both power and carrier signal to transceiver module to momentarily energize ignition key. After energize period has expired, key transmits its identification code to transceiver module. This encoded ignition key is much larger in size than a non-encoded key to accommodate electronics located inside plastic cover.
POWERTRAIN CONTROL MODULE (PCM)
Passive anti-theft system communicates with PCM through the 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 will turn on for 3 seconds, then turn off. Vehicle will be enabled to start and run.
If there is a problem in the system, THEFT indicator will stay on or flash continuously. Go to SELF-DIAGNOSTIC SYSTEM.

Dave H
Jul 26, 2010.


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