Lane Departure Warning Description and Operation: Notes
The lane departure warning system is a convenience feature of the frontview camera module that issues a warning when the system detects that the vehicle has unintentionally crossed a lane marking. The frontview camera module is located behind the windshield, looking out at the road ahead and detecting any lane markings. When the vehicle unintentionally leaves a detected lane, a visual and audible alert is given to the driver.
The lane departure warning system is made up of the following components:
- Frontview camera module
- Lane departure warning switch, part of the steering wheel controls switch - left
- Collision alert indicators, controlled by the instrument cluster
- Radio
Front View Camera Module
The frontview camera module detects visual queues such as lane markings. When it is determined that the vehicle has unintentionally moved outside of the lane, a visual and audible warning is given to the driver. The frontview camera module receives an input from the lane departure warning switch and controls the lane departure warning switch indicator. The frontview camera module also communicates via serial data with the instrument cluster and radio to request visual and audible alerts.
Lane Departure Warning Switch
The lane departure warning switch provides an input to the frontview camera module to turn the lane departure warning system on and off. Pressing and releasing the switch will turn the system on or off. When the system is on, the lane departure warning switch indicator will be illuminated.
The frontview camera module provides a signal voltage to the normally open momentary lane departure warning switch. When the switch is not pressed, the signal circuit is effectively open and voltage observed by the frontview camera module is high. When the switch is pressed, the signal circuit is pulled to ground through a resistor, reducing the voltage observed by the frontview camera module. This will indicate to the frontview camera module that the driver has been requested the system be turned on or off
Voltage is applied to the lane departure warning switch indicator by the body control module (BCM) at all times. The frontview camera controls indicator by providing a controlled ground. When the control circuit is grounded by the frontview camera module, the indicator will be illuminated.
Collision Alert Indicators
The collision alert indicators contains the indicators for the lane departure warning system and are controlled by the instrument cluster via serial data messages from the frontview camera module. When the green lane departure warning indicator is illuminated, the system has detected and is actively monitoring lane marking. The amber lane departure warning indicator will flash if the system determines that the vehicle has unintentionally crossed a lane marking.
Voltage is applied to the collision alert indicators by the body control module (BCM) at all times. The instrument cluster controls each indicator by providing a controlled ground. When the control circuit ground grounded by the instrument cluster, the indicator will be illuminated. The collision alert indicators also contain the forward collision alert indicators.
Radio
The radio controls the audible alert for the lane departure warning. If the vehicle has unintentionally left the lane, the radio will command an audible alert to the driver, as requested by the frontview camera module.