Principles of Operation

PRINCIPLES OF OPERATION

The fire suppression module is non-repairable. The fire suppression module uses hardwired circuitry, internal sensors, internal back-up power supply, the controller area communication network (CAN), and the International Standards Organization (ISO) 9141 communication network. The fire suppression system can be diagnosed with a scan tool through the ISO network. Communication using the CAN circuits transmits and receives data between the fire suppression module, the PCM, and the ABS module. Refer to Information Bus (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 4 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 2 impact sensors located inside the fire suppression module. 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 fire suppression module 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 DTCs are logged.

A manual switch is present as an override to the system. When the manual switch is pressed with the ignition switch in the ON position, it provides voltage and ground to the fire suppression module, at which time the fire suppression module deploys the fire suppressors.