Forward Collision Warning

Forward Collision Warning

Principles of Operation

The forward collision warning system is a safety feature that alerts the driver of a high risk collision. In the event of a possible collision, the red LEDs that are integral to the Head Up Display (HUD) module flashes, a chime from the Instrument Panel Cluster (IPC) activates, and the Audio Control Module (ACM) volume mutes.

The forward collision warning system is activated when the vehicle is moving forward at a speed greater than 8 km/h (5 mph). The Cruise-Control Module (C-CM) determines the distance and relative speed of the vehicle that is in the path of travel, utilizing a radar sensor (integral to the C-CM (Cruise-Control Module)) to detect other vehicles that are moving in the same direction. If the C-CM (Cruise-Control Module) determines that a collision is possible, the C-CM (Cruise-Control Module) sends a network message over the High Speed Controller Area Network (HS-CAN) to the HUD (Head Up Display) module, and the LEDs internal to the module flash.

The forward collision warning system and audible warning chime can be enabled and disabled through the message center display in the IPC (Instrument Panel Cluster). The system reverts to on each ignition cycle. The HUD (Head Up Display) module and/or chime activates briefly to confirm the last setting.

The HUD (Head Up Display) module receives the ignition switch status network message from the Body Control Module (BCM) over the HS-CAN (High Speed Controller Area Network).

For vehicles with a base IPC (Instrument Panel Cluster), the sensitivity of detection is changed in the message center from a high sensitivity (<----->) to a low sensitivity (< ->). For vehicles with an optional IPC (Instrument Panel Cluster), there are three levels of sensitivity detection (LONG, NORMAL and SHORT) that are changed in the message center display.

The forward collision warning system works in conjunction with the adaptive cruise control system. If the vehicle is utilizing the adaptive cruise control feature and is at its maximum braking capability, the C-CM (Cruise-Control Module) sends a forward collision warning display message over the HS-CAN (High Speed Controller Area Network) to the HUD (Head Up Display) module and the LEDs flash. The C-CM (Cruise-Control Module) sends a message over the HS-CAN (High Speed Controller Area Network) of forward collision warning audio level to the IPC (Instrument Panel Cluster), which activates a chime. The C-CM (Cruise-Control Module) sends a message over the HS-CAN (High Speed Controller Area Network) of forward collision audio mute to the IPC (Instrument Panel Cluster). The IPC (Instrument Panel Cluster) gateways the message over the Infotainment Controller Area Network (ICAN) to the ACM (Audio Control Module) and the volume mutes. For more information on the adaptive cruise control system, refer to Fire Suppression System.

If a MyKey(TM) restricted key is in the ignition, the MyKey(TM) turns on the forward collision warning and will not allow the MyKey(TM) user to disable the audio or visual forward collision warning system. However, the MyKey(TM) user is able to adjust the forward collision warning sensitivity.

There are certain situations when the warning LEDs cannot be seen, such as strong sunlight or when wearing sunglasses. The HUD (Head Up Display) module has a temperature sensor circuit that is integral to the module that senses the temperature of the LEDs internal to the module. When a high passenger compartment temperature such as strong sunlight, is sensed by the temperature sensor, the warning LEDs can be temporarily disengaged. If this occurs, only the audible warning chime is used. Warnings may not appear if the distance to the vehicle ahead is very small or if the steering wheel and pedal movements are large, for example, due to a very active driving style.

When a system fault is detected with the forward collision warning system the message COLLISION WARN NOT AVAILABLE, COLLISION WARN NOT AVAILABLE SENSOR BLOCKED, or COLLISION WARNING MALFUNCTION is displayed in the IPC (Instrument Panel Cluster) message center.

Network Communication

The following forward collision warning system components communicate via the HS-CAN (High Speed Controller Area Network) :

- HUD (Head Up Display) module

- C-CM (Cruise-Control Module)

- ABS module

- IPC (Instrument Panel Cluster)

- BCM (Body Control Module)