Component Tests and General Diagnostics

Sensing and Diagnostic Module (SDM) Integrity Check

The following diagnostic chart must be used when all circuitry outside the Sensing and Diagnostic Module (SDM) has been found to operate properly, as indicated by following the appropriate Diagnostic Trouble Code (DTC) chart. The chart verifies the need for SDM replacement.

Circuit Description
When the SDM recognizes ignition voltage greater than 9 V at terminal 26 of the SDM, 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, B1651, B1652, B1657 and B1670. DTC B1620, B1650, B1651, B1652, B1657 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.

Troubleshooting

WARNING:
^ The Sensing and Diagnostic Module (SDM) can maintain sufficient voltage to deploy the airbags and pretensioners for 1 minute after the ignition is OFF and the fuse has been removed. If the airbags and pretensioners are not disconnected, do not begin service until 1 minute has passed after disconnecting the power to the SDM. Otherwise, injury could result.
^ During service procedure, be very careful when handling the SDM. Never strike or jar the SDM. Never power the Supplemental Inflatable Restraints (SIR) when the SDM is not rigidly attached to the vehicle. All SDM mounting bolts must be carefully tightened, and the arrow on the SDM must be point toward the front of the vehicle to ensure proper operation of the SIR. The SDM could be activated if it is powered when it is not rigidly attached to the vehicle, resulting in unexpected deployment and possible injury.

Step 1-4:

Hot in Run and Start

Hot In Run And Start: