Forward Collision Warning

Overview

The forward collision warning system alerts the driver of a collision risk with a red warning LED indicator bar located above the instrument panel (part of the HUD module) and an audible warning chime from the IPC . The ABS module uses 3 braking strategies based on inputs from the C-CM .

System Operation

System Diagram

Network Message Chart

 Module Network Input Messages — ACM

 Module Network Input Messages — C-CM

 Module Network Input Messages — HUD

 Module Network Input Messages — IPC

 Module Network Input Messages — ABS Module

Collision Warning With Brake Support

The forward collision warning system works in conjunction with the adaptive cruise control system. During a possible collision event, the C-CM commands:

• the HUD module to flash red warning LEDs.
• the IPC to activate a chime and messages.
• the ACM to mute audio volume.
• the ABS module to apply one of 3 braking strategies.

The forward collision warning system is activated when the vehicle is moving forward at a speed greater than 8 kmh (5 mph). The 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 ) to detect other vehicles that are moving in the same direction. If the C-CM determines that a collision is possible, the C-CM commands the HUD module LEDs to flash, the ABS module to one of the three braking strategies, and the IPC to chime.

There are 3 braking strategies that are part of the Collision Warning system:

• Pre-charge level 1 - a light brake pre-charge when a collision is possible.
• Pre-charge level 2 - a slightly higher brake pre-charge when a collision is possible and the driver lifts his foot off of the accelerator pedal.
• Full braking - is applied when a collision is possible and the driver presses the brake pedal lightly.

The forward collision warning system and audible warning chime can be enabled and disabled through the message center display in the IPC . The system reverts to ON each ignition cycle. The HUD module and/or chime activates briefly to confirm the last setting. For vehicles with a base IPC , the sensitivity of detection is changed in the message center from a high sensitivity ( <----->) to a low sensitivity ( <->).

For vehicles with an optional IPC , there are 3 levels of sensitivity detection (LONG, NORMAL and SHORT) that are changed in the message center display.

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

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 message center.

Component Description

Cruise Control Module (C-CM)

The C-CM contains a radar sensor unit that determines the distance and relative speed of the vehicle that is in the path of travel.

Head Up Display (HUD) Module

The HUD module contains the red LEDs that warn the driver of a possible collision event when commanded by the C-CM . There are certain situations when the warning LEDs cannot be seen, such as strong sunlight or when wearing sunglasses. The HUD 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.