CIRCUIT TEST R - CODE 51, DIAGNOSTIC MONITOR INTERNAL THERMAL FUSE OPEN
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 the thermal fuse in the diagnostic monitor.
NOTE:Before proceeding, follow air bag service precautions. See SERVICE PRECAUTIONS. After repairs are performed, recheck AIR BAG warning light for other fault codes. Perform system operation check. See TESTING - SYSTEM OPERATION CHECK.
NOTE:A thermal fuse is built into the diagnostic monitor. If a short to ground should occur in the air bag deployment circuit, the microcomputer in the diagnostic monitor will send a signal to the fuse causing it to open. The open fuse removes all firing power (battery/back-up power) from the deployment circuits. This prevents unwanted air bag deployments due to damaged vehicle wiring.
Initial Test Procedure
After repairing wiring for a short to ground, check AIR BAG warning light for codes. See TESTING - SYSTEM OPERATION CHECK. If AIR BAG warning light indicates Code 51, deactivate SRS. See COMPLETE SYSTEM DEACTIVATION under DISABLING & ACTIVATING AIR BAG SYSTEM. Replace diagnostic monitor. When repairs are complete, check AIR BAG warning light for codes with Air Bag Simulator(s) (105-00008) still in place of air bag module(s). See TESTING - SYSTEM OPERATION CHECK. If system checks okay, reactivate SRS.
NOTE:Code 51 is displayed whenever the diagnostic monitor thermal fuse is open and no other higher priority faults exist. Code 51 is normally seen after service of a Code 13 condition. If a Code 51 exists and a Code 13 condition has not been serviced, an intermittent short to ground exists in the air bag deployment circuit. The intermittent short to ground must be located and serviced before servicing the Code 51 condition.
Monday, January 25th, 2010 AT 12:39 PM