Principles of Operation: Notes

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. 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 front door side impact sensors
Driver and passenger second row C-pillar side impact sensors
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 information received from 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 pretensioner(s)
Safety belt adaptive load limiting retractor (driver seat only)
Safety Canopy®
Seat side airbag(s)
Driver and passenger dual-stage airbags (one or both stages)
Deployable steering column

The fact the safety belt retractor pretensioner(s) or airbags did not activate for both front seat occupants in a crash does not mean that something is wrong with the SRS .

The RCM performs a self-test of the complete SRS during start up. During normal operation, the Instrument Panel Cluster (IPC) illuminates the airbag warning indicator continuously for 6 seconds. If the SRS is free of faults, the airbag warning indicator turns off and remains off. If a SRS fault exists, the airbag warning indicator illuminates and remains illuminated for the rest of the ignition cycle. The RCM communicates to the IPC via the High Speed Controller Area Network (HS-CAN). The IPC illuminates the airbag warning indicator based on messaging from the RCM or if there is no communication between the RCM and IPC . In addition to the self-test at start up, the RCM continuously monitors all of its SRS components and circuitry for correct operation.