Principles of Operation

WARNING: This page is about a different car, the 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

The fire suppression module is non-repairable. The fire suppression module uses hardwired circuitry, internal sensors, internal back-up power supply, the controller area network (CAN), and the International Standards Organization (ISO) 9141 network. The fire suppression system can be diagnosed with a diagnostic tool through the ISO network. Communication using the CAN circuits transmits and receives data between the fire suppression module, the powertrain control module (PCM), and the anti-lock brake system (ABS) module. For additional information regarding the communication network, refer to MODULE COMMUNICATIONS NETWORK .

It is very important to understand:

where the input originates.
all the information necessary in order for a feature to operate.
which module(s) receive(s) the input or command message.
whether the module which received the input controls the output of the feature, or whether it outputs a message over the CAN network to another module.
which module controls the output of the feature.

The fire suppression module detects high velocity rear impacts, determines vehicle motion, and deploys up to four suppressor squibs based on vehicle motion requirements. Deployment of the suppressor squibs activates the disbursement of a fire suppression material beneath the rear portion of the vehicle. A rear collision is sensed by two impact sensors located inside the FSM. Vehicle motion after impact is determined based on deceleration and wheel speed. The vehicle identification number (VIN), model year, and wheel speed information is received by the FSM through the CAN communication network.

If the fire suppression module detects a problem with any of the fire suppression system components, an indicator in the instrument cluster is illuminated and diagnostic trouble codes (DTCs) are logged.

A manual activation switch is present as an override to the system. When the manual activation switch is pressed with the ignition lock cylinder in the ON position, it provides voltage and ground to the FSM and then the FSM deploys the fire suppressors.