Principles of Operation: Notes

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The Restraints Control Module (RCM) continuously receives/monitors all inputs from the following Supplemental Restraint System (SRS) components.

LH and RH front impact severity sensor
Driver and Passenger front door side impact sensor
Driver and Passenger C-pillar side impact sensor
Safety belt buckle switches (driver and passenger)
Driver seat track position sensor
Occupant Classification System Module (OCSM)

If the RCM detects sudden vehicle deceleration and/or lateral deceleration based on all the information received from all sensors and switches and determines that deployment is required, the RCM sends voltage and current to deploy the appropriate SRS components.

During a frontal or side crash, the RCM may deploy the following SRS components, based on crash severity and sensor input.

Safety belt retractor pretensioner(s)
Seat side air bag(s)
Side air curtain(s)
Driver/passenger dual-stage air bag (one or both stages)

The fact that the safety belt retractor pretensioners, side air curtains and side air bags did not activate for both front seat occupants in a crash does not mean that something is wrong with the system.

The RCM performs a self-test of the SRS during each startup. If a SRS fault exists, the air bag warning indicator will illuminate and remain illuminated for the rest of the ignition cycle. In addition to the self-test at start up, the RCM continuously monitors all of its SRS components and circuitry for correct operation.