Circuit Description

When the SDM recognizes ignition voltage greater than 9 V at terminal 26 of the SDM connector, the airbag indicator flashes seven times to verify operation. At this time the SDM performs turn-on tests followed by resistance measurement tests and continuous monitoring tests.

When malfunction is detected, the SDM sets current DTC and illuminates the airbag indicator. When the malfunction is no longer detected and/or the ignition switch is cycled, the SDM will clear current DTCs and move them to a history file, except for the DTC B1620, B1650 and B1670. DTC B1620, B1650 and B1670 will not be cleared by scan tool because these codes require replacement of SDM. The SDM must be replaced only after the malfunction that set the DTC has been repaired.