Principles of Operation: Notes

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. 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 sensors
Driver and passenger first row side impact sensor B-pillar
Driver and passenger second row side impact sensors C-pillar
Safety belt buckle switches (driver and passenger)
Driver seat track position restraints sensor
Occupant Classification System Module (OCSM)

If the RCM detects sudden vehicle deceleration and/or lateral deceleration based on 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.

The RCM contains an internal sensor that detects vehicle rollover angles. If the RCM determines that a rollover condition exists and deployment is required, the RCM deploys the applicable 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(s)
Safety belt buckle pretensioner(s)
Safety canopies®
Seat side air bag(s)
Driver and passenger dual-stage air bag(s) (one or both stages)

The fact that the safety belt buckle pretensioners, safety belt retractor(s) or 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 complete 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.