Swift GL L4-1298cc 1.3L SOHC MFI (2000)
Sensing and Diagnostic Module: Description and Operation
System Description
The air bag system consists of the Sensing and Diagnostic Module (SDM), the forward (discriminating) sensor, the driver air bag (inflator) module, the
contact coil assembly, the passenger air bag (inflator) module and the "AIR BAG" warning lamp in the instrument cluster. The SDM, contact coil
assembly (driver side only), driver air bag (inflator) module, passenger air bag (inflator) module and connector wires makeup the deployment loops. The
function of the deployment loops is to supply current through the air bag (inflator) modules, which will cause deployment of the air bags in the event of a
frontal crash of sufficient force, up to 30 degrees off the centerline of the vehicle. The air bag (inflator) modules are only supplied enough current to
deploy when the SDM or the SDM and the forward (discriminating) sensor detect vehicle velocity changes severe enough to warrant deployment.
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 signal processing is performed and
the generated 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 air bag
(inflator) modules deploying the air bags.
