Vehicle Security Module
WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The vehicle security module is on the ISO 9141 communications network. The vehicle security module controls the remote keyless entry (RKE) function as well as the power door locks. The ISO 9141 communications network does not function if the circuit is shorted to ground or battery voltage. Check the communications network circuit 70 (LB/WH) between the vehicle security module C203b and the DLC C251. The total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communications network, damage to the DLC C251, damage to the vehicle security module C203b, or a problem in the in-line connector. For additional information, refer to MULTIFUNCTION ELECTRONIC MODULES .