DTC 18 - Discriminating Sensor Interconnect Open: Description
WARNING: This page is about a different car, the 1995 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
During INITIATOR ASSEMBLY RESISTANCE tests, DERM first grounds DRIVER-SIDE LOW terminal B8, then monitors voltage at both DRIVER-SIDE LOW and PASSENGER-SIDE LOW. DERM then grounds PASSENGER-SIDE LOW terminal B7 and again measures voltage at DRIVER-SIDE LOW and PASSENGER-SIDE LOW.