Forward Collision Alert Description and Operation
The forward collision alert system is a convenience feature of the B174W Frontview Camera - Windshield that issues a warning to the driver when a potential collision risk exists. The B174W Frontview Camera - Windshield is located behind the windshield, looking out at the road ahead and detecting vehicles directly ahead. When the system detects a vehicle in the path ahead, the green vehicle ahead indicator is illuminated on the instrument cluster. When approaching another vehicle too rapidly, the P43 Collision Alert Indicators, which includes a series of red collision alert indicators, will flash. An audible alert sound will simultaneously sound. The forward collision alert system can also be turned on or off through the vehicle personalization menus. See the vehicle owner's manual for more detailed information on vehicle personalization.
Forward collision alert does not provide a warning to help avoid a crash, unless it detects a vehicle. Forward collision alert may not detect a vehicle ahead if the B174W Frontview Camera - Windshield is blocked by dirt, snow, or ice, or if the windshield is damaged. It may also not detect a vehicle on winding or hilly roads, or in conditions that can limit visibility such as fog, rain, or snow, or if the headlamps or windshield are not cleaned or in proper condition. Keep the windshield, headlamps, and B174W Frontview Camera - Windshield area clean and in good repair.
Forward collision alert may provide unnecessary alerts for turning vehicles, vehicles in other lanes, objects that are not vehicles, or shadows. These alerts are normal operation and the vehicle does not need service.
The forward collision alert system is made up of the following components:
- B174W Frontview Camera - Windshield
- P16 Instrument Cluster
- P43 Collision Alert Indicators
- Forward Collision Alert Switch
- Infotainment System
B174W Frontview Camera - Windshield
The B174W Frontview Camera - Windshield detects vehicles in front of the vehicle. The B174W Frontview Camera - Windshield communicates with the P16 Instrument Cluster via serial data to illuminate the appropriate amber or green vehicle ahead indicator or P43 Collision Alert Indicators. The B174W Frontview Camera - Windshieldalso communicates via serial data with the infotainment system to request audible alerts.
P16 Instrument Cluster
The P16 Instrument Cluster communicates via serial data with the B174W Frontview Camera - Windshield and will illuminate the amber or green vehicle ahead indicator as requested by the B174W Frontview Camera - Windshield. The P16 Instrument Cluster also controls the P43 Collision Alert Indicators.
P43 Collision Alert Indicators
The P43 Collision Alert Indicators are a series of red LEDs that will flash when approaching another vehicle too rapidly. The P43 Collision Alert Indicators are located in the upper instrument panel area and reflect off the windshield when illuminated.
The P43 Collision Alert Indicators receive power and ground and are discretely controlled by the P16 Instrument Cluster through a pair of low control circuits. When requested by the B174W Frontview Camera - Windshield, the P16 Instrument Cluster will pulse the low control circuits, flashing the LEDs as a visual alert that another vehicle is being approached too rapidly.
Forward Collision Alert Switch
The forward collision alert switch provides an input to the B174W Frontview Camera - Windshield to select the alert timing sensitivity when approaching another vehicle too rapidly. The forward collision alert switch is part of the S155 Lane Departure Warning Switch.
The K9 Body Control Module applies voltage and monitors a low signal voltage from the normally open switch. When the switch is pressed, the signal circuit is pulled low through a specific series of resistors, indicating that the system has been requested to change the alert timing sensitivity. The first button press will show the current alert timing setting on the driver information center. With every subsequent button press, the alert timing sensitivity is changed.
Infotainment System
The infotainment system controls the audible alerts for the forward collision alert system. If the vehicle is approaching another vehicle too rapidly, the B174W Frontview Camera - Windshield will command the infotainment system issue an audible alert to the driver.