Inflatable Restraint Sensing and Diagnostic Module

The inflatable restraint Sensing and Diagnostic Module (SDM) performs the following functions in the SIR system:
^ Energy Reserve - The SDM maintains a 23 Volt Loop Reserve (23 VLR) energy supply to provide deployment energy for the air bags. Ignition voltage can provide deployment energy if the 23 Volt Loop Reserves malfunction.
^ Crash Detection
- Frontal - The SDM monitors vehicle velocity changes in order to detect frontal crashes that are severe enough to warrant deployment.
- Side - The SDM monitors vehicle velocity changes along with SIS information in order to detect side impact crashes that are severe enough to warrant deployment.
^ Air Bag Deployment
- Frontal - During a frontal crash of sufficient force, the SDM will cause enough current to flow through the frontal inflator modules to deploy the frontal air bags.
- Side - During a side crash of sufficient force, the SDM will cause enough current to flow through the side impact module to deploy the driver side air bag.
^ Frontal Crash Recording - The SDM records information regarding the SIR system status during a frontal crash.
^ Side Impact System Malfunction Monitoring - The SDM monitors the SIS. The SIS can communicate the status of the side impact air bag system to the SDM.
^ Malfunction Detection - The SDM performs diagnostic monitoring of the SIR system electrical components. Upon detection of a circuit or component malfunction, the SDM will set a DTC.
^ Malfunction Diagnosis - The SDM displays SIR DTCs and system status information through the use of a scan tool.
^ Driver Notification - The SDM notifies the vehicle driver of SIR system malfunctions by controlling the AIR BAG warning lamp in the instrument cluster via Class 2 serial data.

The SDM connects to the SIR wiring harness using the following connector(s):
^ The 18-way connector provides power, ground, and all the required interfaces for frontal air bag deployment.
^ The 8-way connector (AJ7) provides all the required interfaces for side impact sensing and side air bag deployment.

The SDM receives power whenever the ignition is ON.