Side Impact Component Description

CAUTION: Be careful when you handle an inflatable restraint Side Impact Sensing Module (SISM). Do not strike or jolt the SISM. Before applying power to the SISM:
^ Remove any dirt, grease, etc. from the mounting surface.
^ Position the SISM on the mounting surface.
^ Point the connector on the SISM toward the rear of the vehicle.
^ Tighten all of the SISM fasteners to the specified torque value.
Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary Air Bag system repairs.

The inflatable restraint Side Impact Sensing Modules (SISM) perform the following functions in the air bag system.
^ Energy Reserve - Each SISM maintains a 23 Volt Loop Reserve (23 VLR) energy supply to provide deployment energy. Ignition voltage can provide deployment energy if the 23 Volt Loop Reserve malfunctions.
^ Side Impact Crash Detection - Each SISM monitors door velocity changes to detect side impact crashes which are severe enough to warrant deployment.
^ Side Impact Air Bag Deployment - When a side impact crash of sufficient force is detected, the SISM on the side of the impact will cause enough current to flow through the respective inflator module to deploy the side impact air bag.
^ Malfunction Detection - The SISM performs diagnostic monitoring of the RH or LH side impact SIR system electrical components, respectively, and sets a diagnostic trouble code when a malfunction is detected.
^ Side Air Bag System Status Communication - The inflatable restraint Sensing and Diagnostic Module (SDM) monitors a diagnostic line from each SISM. Both SISMs communicate the status of the side impact air bag system to the SDM over this diagnostic lines. The following table shows what signals are sent over this diagnostic line and when the signals are sent.

The inflatable restraint Side Impact Sensing Module (SISM) connects to the air bag wiring harness using a 5-way connector.

The inflatable restraint Side Impact Sensing Module (SISM) receives power whenever the ignition switch is at the RUN or START positions. The SISM and the inflatable restraint Sensing and Diagnostic Module (SDM) are powered by the SIR Fuse.