Fire Suppression System: Description and Operation
Fire Suppression System
WARNING: The fire suppression system backup power supply must be depleted before lifting the vehicle or when repairing or replacing any of the following:
- Fire suppression system components
- Components located near the fire suppression manual switch
- Fuel tank and components located near the fuel tank
- Rear axle and components located near the rear axle
To deplete the backup power supply, disconnect the battery and wait at least 1 minute. Be sure to disconnect all auxiliary batteries and power supplies (if equipped). Failure to follow these instructions may result in serious personal injury.
The fire suppression system helps reduce the risk of fire in high speed rear impacts. The fire suppression system deploys a fire suppressant chemical to suppress the spread of fire or potentially extinguish a fire allowing occupants more time to escape from the vehicle.
The fire suppression system can be activated:
- automatically during a high speed rear impact.
- manually from the fire suppression manual switch.
In the event of a fire suppression deployment, the fire suppression manifold nozzles deploy downward and discharge a fire suppressant chemical under the vehicle and around the fuel tank.
NOTICE: After system deployment, the fire suppression manifold nozzles may need to be secured in the up position before driving the vehicle through an automatic car wash, or they may come in contact with the automatic car wash components causing damage to the fire suppression nozzles and vehicle.
The fire suppressant chemical contains no hazardous materials (but can cause minor skin or eye irritation) and can be readily cleaned up by flushing the vehicle underbody with water or soap and water. Manual deployment should have no effect on vehicle handling.
NOTE: In the event of a fire suppression system deployment, new fire suppression components must be installed. The fire suppression manual switch is only replaced if the switch cover was damaged during a manual activation event.
The fire suppression system consists of the following components:
- Fire Suppression System Module (FSSM)
- Fire suppression manual switch (located in the overhead console)
- LH and RH external fire suppressors actuators (if equipped)
- LH and RH fire suppressors
- LH and RH fire suppression manifolds
- Fire Suppression Indicator Lamp (FSIL) (part of the Instrument Cluster (IC))
Fire Suppression System Module (FSSM)
WARNING: The tightening torque of the fire suppression system module (FSSM) bolts and the FSSM orientation on the body of the vehicle is critical for correct system operation. Always tighten and orient the FSSM per specifications. Failure to do so may result in incorrect fire suppression system operation, which increases the risk that it will not protect vehicle occupant(s).
The FSSM is mounted underneath the rear seat cushion. The FSSM carries out the following functions:
- Signals the fire suppressors or external fire suppressor actuators (if equipped) to deploy the fire suppressant chemical in the event of a deployable crash.
- Monitors the fire suppression system for faults.
- Illuminates the FSIL if a fault is detected.
- Receives information from the ABS module on the High Speed Controller Area Network (HS-CAN).
- Receives information from the PCM on the HS-CAN.
- Communicates any on-demand or Continuous Memory Diagnostic Trouble Codes (CMDTCs) retrieved by the scan tool to the Data Link Connector (DLC) through the International Organization for Standardization (ISO) 9141 communication network.
The FSSM monitors the fire suppression system for faults. If a fault is detected with the ignition ON, the FSSM illuminates the FSIL.
When the ignition is cycled (turned off and then on), the FSIL illuminates for 6 seconds and then goes out if no fault is detected. If a fire suppression system fault exists, the FSIL flashes or remains steadily on. The FSSM uses the scan tool to communicate the on-demand and CMDTCs through the DLC.
The FSSM includes a backup power supply. This feature provides sufficient backup power to deploy the fire suppressors in the event the ignition circuit is lost or damaged during impact before the fire suppressors or external fire suppressor actuators (if equipped) are activated. The backup power supply depletes its stored energy approximately one minute after power and/or ground has been removed from the FSSM.
Fire Suppression Manual Switch
The fire suppression manual switch allows for manual deployment of the fire suppression system. Manual deployment of the fire suppression system is possible only when the ignition switch is in the ON position.
Fire Suppressors
Fire Suppressor without External Actuators
WARNING: To reduce the risk of accidental deployment, never probe the connectors on the fire suppressors. Failure to follow this instruction may cause unintentional deployment of the suppressors, which may result in serious personal injury.
Upon receiving voltage from the FSSM, the fire suppression squibs ignite causing a chemical reaction to occur inside the fire suppression containers. A fire suppressant chemical is then deployed from the fire suppression containers and discharged through the fire suppression manifolds.
The fire suppressors are mounted below the rear axle on the No. 4 crossmember.
Fire Suppressor with External Actuators
WARNING: To reduce the risk of accidental deployment, never probe the connectors on the fire suppressors. Failure to follow this instruction may cause unintentional deployment of the suppressors, which may result in serious personal injury.
Upon receiving voltage from the FSSM, the external fire suppressor actuator squibs ignite causing a rapid discharge of high pressure Helium gas from the external fire suppressor actuator containers into the fire suppressor containers and discharged through the fire suppression manifolds.
The external fire suppressor actuators are attached to the fire suppressors and mounted above the rear axle on the No. 4 crossmember.
Fire Suppression Manifolds
The fire suppression manifolds deploy downward and discharge a fire suppressant chemical under the vehicle and around the fuel tank. The fire suppression manifolds are mounted on the fire suppressors.
Electrical System
The electrical system that supports the fire suppression system:
- is powered by the battery through the ignition circuit.
- provides the electrical path from the FSSM to the fire suppressors (without external fire suppressor actuators).
- provides the electrical path from the FSSM to the external fire suppressor actuators (if equipped).
- provides the electrical path from the fire suppression manual switch to the FSSM.
- provides the electrical path from the FSSM to the FSIL.
- provides the electrical path from the FSSM to the DLC.
- provides the electrical path from the FSSM to the PCM.