Air Bag Control Module: Description and Operation
DESCRIPTIONThe Sensing and Diagnostic Module (SDM) performs several system functions. These functions include energy reserve, air bag deployment, malfunction detection, malfunction diagnosis, driver notification, frontal crash detection and frontal crash recording.
OPERATION
The SDM contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal generated is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signals are compared to signals stored in memory. When two of the generated signals exceed the stored values or when one of the generated signals exceeds the stored value and the forward discriminating sensor closes, the SDM will cause current to flow through the inflator modules deploying the air bags.