Air Bag Control Module: Description and Operation
SDM (SENSING AND DIAGNOSTIC MODULE)WARNING:
- During service procedures, be very careful when handling a Sensing and Diagnostic Module (SDM).
- Be sure to read SERVICE PRECAUTIONS and HANDLING PRECAUTIONS before starting to work and observe every precaution during work. Neglecting them may result in personal injury or undeployment of the air bag when necessary.
CAUTION: After detecting one time of such collision as to meet deployment condition, the SDM must not be used. Replace with new one. Refer to DIAGNOSIS when checking the SDM.
Sensing and Diagnostic Module (SDM) is designed to perform the following functions in air bag system:
1. Energy Reserve
SDM maintains Reserve energy supply to provide deployment energy after ignition voltage is lost in a frontal crash.
2. Frontal Crash Detection
SDM monitors vehicle velocity changes to detect frontal crashes which are severe enough to warrant deployment.
3. Air Bag Deployment
When a frontal crash of sufficient force is detected, SDM will cause enough current to flow through air bag (inflator) modules to deploy air bags.
4. Malfunction Detection
SDM performs diagnostic monitoring of air bag system electrical components and sets a diagnostic trouble code (DTC) when a malfunction is detected.
5. Malfunction Diagnosis
SDM displays air bag diagnostic trouble codes (DTCs) and system status information through the use of special tool (SUZUKI scan tool).
SDM with on-board diagnostic function provides air bag diagnostic trouble codes by flashing 'AIR BAG" warning lamp when on-board diagnosis function is used.
6. "AIR BAG" Warning Lamp Control
The light is turned "ON" to warn the driver of occurrence of a trouble and made to flash to check burned bulb of "AIR BAG" warning lamp.
7. Communication with SUZUKI scan tool
DTC display or DTC clear.
In response to the output request from SUZUKI scan tool, DTC recorded in the memory, each initiator circuit resistance and ignition voltage as recognized by SDM at time of the output request are provided.
SDM Connector
Connector lock lever:
The purpose of the connector lock lever is to assure the connector halves are securely connected and they cannot vibrate apart.
Shorting bar:
Connector "A" has a short mechanism which connects the "AIR BAG" lamp circuit to the ground while the connector is disconnected from SDM. When connected to SDM securely, it is automatically cancelled.
Terminal retainer (Terminal position assurance: TPA):
The function of the TPA is to keep the terminal securely seated in the connector body. The TPA is not to be removed from the connector body.
Terminal retainer (Terminal position assurance: TPA):
The function of the TPA is to keep the terminal securely seated in the connector body. The TPA is not to be removed from the connector body.