Normal Operation
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The 4WD control module communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). If one of the bus wires becomes shorted to ground or voltage, communication can continue at a reduced level. Check circuits 1908 (WH) and 1909 (BK) between the 4WD control module C3253 and the data link connector (DLC) C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to the 4WD control module C3253, or a problem in an in-line connector.