Code 51, Diagnostic Monitor Internal Thermal Fuse Open: Notes
WARNING: This page is about a different car, the 1993 Mercury Sable, 1993 Lincoln Continental, and 1993 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Before proceeding, see SERVICE PRECAUTIONS. After servicing has been performed, recheck AIR BAG warning light for codes with Air Bag Simulator (105-00010) still in place of air bag module. If system is okay, install air bag module and reactivate air bag system.
NOTE:
A thermal fuse is built into diagnostic monitor. If a short to ground should occur in air bag deployment circuit, microcomputer in diagnostic monitor will send a signal to fuse, causing it to open. Open fuse removes all firing power (battery/back-up power) from deployment circuits. This prevents unwanted air bag deployments due to damaged vehicle wiring.
CAUTION:
Never replace diagnostic monitor without first determining cause for Code 51 condition. If short to ground is not properly serviced, short may reoccur, once again destroying diagnostic monitor thermal fuse.
NOTE:
Code 51 is displayed whenever diagnostic monitor thermal fuse is open and no higher priority faults exist. Code 51 is normally seen after service of a Code 13 or 14. If a Code 51 exists and Code 13 or 14 has not been serviced, an intermittent short to ground exists in air bag deployment wiring. Intermittent short to ground must be located and serviced before servicing Code 51.