Test H: Air Bag Diagnostic Monitor Ground Circuit Open (DTC B1921): Description
WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.
Restraints Control Module (RCM) monitors resistance between ground connections at its mounting bracket and reference ground at RCM connector C310A, terminal No. 16. If RCM detects a difference in resistance, it stores DTC B1921 in memory and flashes Code 1-4 on AIR BAG warning light.