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 is designed to help reduce the risk of fire in high speed rear impacts. The fire suppression system deploys chemicals designed to suppress the spread of fire or potentially extinguish a fire, thereby providing more time for occupants to escape from a crashed vehicle.

The fire suppression system can be activated:

- automatically when a high speed, high energy rear impact has occurred.
- manually when other situations require fire suppression.

In the event of a fire suppression system manual deployment, the fire suppression manifold nozzles will deploy to near ground level and the underbody of the vehicle will be covered with fire suppressant fluid.

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.

The suppressant contains no hazardous materials (but may 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: These components must be replaced with new components in the event of a fire suppression system manual deployment. A new fire suppression manual switch must be installed only if the switch cover was damaged during the manual activation.

The fire suppression system consists of the following components:

- Fire Suppression System Module (FSSM)
- Fire suppression manual switch
- Fire suppressors
- Fire suppression manifolds
- Fire suppression system indicator (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 Fire Suppression System Module (FSSM) is mounted underneath the rear seat cushion. The FSSM carries out the following functions:

- Signals the suppressors to deploy the suppressant material in the event of a deployable crash.
- Monitors the fire suppression system for faults.
- Illuminates the fire suppression system indicator 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 through the ISO 9141 communication network to the Data Link Connector (DLC) any on-demand or continuous memory DTCs, retrieved by the scan tool.

The FSSM monitors the fire suppression system for possible faults. If a fault is detected while the ignition switch is in the ON position, the FSSM will illuminate the fire suppression system indicator located in the IC.

When the ignition switch is cycled (turned off and then on), the fire suppression system indicator remains lit for 6 seconds and then goes out. If a fire suppression fault exists, the fire suppression system indicator flashes or remains lit. The FSSM communicates the on-demand and continuous memory DTCs through the DLC, using the scan tool.

The FSSM includes a backup power supply. This feature provides sufficient backup power to deploy the suppressors in the event that the ignition circuit is damaged in a collision before the suppressors deployment is initiated. The backup power supply will deplete its stored energy approximately one minute after the power is removed from the FSSM.

Fire Suppression Manual Switch

The fire suppression manual switch allows for manual deployment of the suppressors in the event of a fire, when the system has not deployed automatically. Manual activation is possible only when the ignition switch is in the ON position.

The fire suppression manual switch is located in a console on the headliner between the sun visors.

Fire Suppressors

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.

The fire suppressors deploy upon receiving voltage from the FSSM.

The fire suppressors are mounted above the rear axle on the No. 4 crossmember.

Fire Suppression Manifolds

The fire suppression manifolds spread the fire suppressant material under the vehicle and around the fuel tank in an event of fire suppression system deployment.

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.
- provides the electrical path from the fire suppression manual switch to the FSSM.
- provides the electrical path from the FSSM to the fire suppression system indicator.
- provides the electrical path from the FSSM to the DLC.
- provides the electrical path from the FSSM to the PCM.