GM Service Manual Online
For 1990-2009 cars only

Object Detection Description and Operation Lane Departure Warning

The lane departure warning system is a convenience feature that issues a warning when the system detects that the vehicle has unintentionally crossed a lane marking. The lane departure warning system is controlled by a camera located behind the windshield which looks out at the road ahead and detects any lane markings. When the vehicle leaves a detected lane without using a turn signal, a visual and audible alert is given to the driver.

The lane departure warning system is made up of the following components:

    • Vehicle direction alert alarm warning module (VDAAW)
    • Lane departure warning switch
    • Instrument panel cluster (IPC)
    • Radio

Vehicle Direction Alert Alarm Warning Module

The vehicle direction alert alarm warning module (VDAAW) controls the lane departure warning system based on the visual inputs received by the camera, which is part of the VDAAW. The camera detects visual queues such as lane markings, curbs, guard rails, and fences. 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 VDAAW receives an input from the lane departure warning switch and controls the lane departure warning LED output. The VDAAW also communicates via serial data with the instrument panel cluster (IPC) and radio to request visual and audible alerts.

Lane Departure Warning Switch

The lane departure warning switch provides an input to the VDAAW to turn the lane departure warning system ON and OFF. The lane departure warning switch is part of the headlamp switch assembly. The VDAAW provides a signal voltage to the normally open momentary switch. When the switch is pressed, the signal circuit is pulled to ground, indicating to the VDAAW that the system has been request to turn ON or OFF.

The lane departure warning switch also contains the lane departure warning LED, which is controlled by the VDAAW to indicate the ON and OFF status of the lane departure warning system. When the system is has been enabled by the lane departure warning switch, the VDAAW applies 12 volts, illuminating the LED.

Instrument Panel Cluster

The instrument panel cluster (IPC) contains the green and amber land departure warning indicators. These indicate to the driver the current status of the lane departure warning system and are controlled via serial data by the VDAAW. When the system has detected the required lane markings and is ready to assist, the green indicator will be illuminated on the IPC. If the vehicle has unintentionally left the lane, the amber indicator will flash.

Radio

The radio controls the audible alert for the lane departure indicator. If the vehicle has unintentionally left the lane, the radio will command 3 beeps as an audible alert to the driver.

System Operation

System operation can be describe by the following modes:

    • Disabled: The system has disabled by the operator, using the lane departure warning switch. The lane departure warning LED will not be illuminated.
    • Not Ready To Assist: The system is enabled and the lane departure warning LED is illuminated, but not ready to assist when any of the following conditions is true:
       - Vehicle speed is less than 35 mph or vehicle speed has dropped below 30 mph when the system initially was in the ready to assist mode. The system is designed to function at speeds greater than 35 mph.
       - The system cannot detect lane markings. This may be because there are no lane markings, as on a country road, or that the lane markings cannot be determined due to snow, rain, or other driving conditions.
       - The windshield area in front of the camera or the camera lens is blocked by fog, dirt, damage to the windshield, or other elements that may prevent the camera from detecting lane markings.
    • Ready To Assist: The system is enabled and ready to warn of the unintentional lane crossing. The system is ready to assist when the green lane departure warning indicator is illuminated on the IPC.

Lane Crossing Alerts

    • The system will not give alerts under the following conditions:
       - The correct turn signal is activated. An activated turn signal is interpreted as an intentional lane crossing.
       - The operator makes a sharp maneuver.
       - The operator makes a significant acceleration change or significant steering change during a lane crossing.
    • Lane crossing alert consists of the following:
       - Three chimes are activated through the radio.
       - The amber lane departure warning indicator will flash.

Lane Departure Warning System DIC Messages

The VDAAW system commands the DIC to display the following messages to alert the driver of a system concern or status information:

    • LANE DEPARTURE SYSTEM UNAVAILABLE
    • SERVICE LANE DEPARTURE SYSTEM

Object Detection Description and Operation Side Blind Zone Alert

The side blind zone alert (SBZA) system is designed to detect vehicles or other objects that may be located in the vehicles blind spots. This detection is performed by two side object sensors, located behind the rear fascia on each side of the vehicle. When an object is detected in a blind spot, an indicator in the outside rearview mirror will illuminate, notifying the driver that it is unsafe to change lanes.

The SBZA system is made up of the following components:

    • Left side object sensor
    • Right side object sensor
    • Driver door module
    • Passenger door module
    • Driver outside rearview mirror
    • Passenger outside rearview mirror

Side Object Sensors

The side object sensors are each located behind the rear fascia, positioned so that the sensor is pointing out toward the opposite lane. Each sensor is supplied B+ and ground. The right sensor receives an additional ground. Both sensors communicate independently on the serial data line. The serial data enters the right sensor in a pass-thru configuration, the connects to the left sensor. The scan tool is able to individually communicate with each sensor.

When a vehicle or object is detected by a side object sensor, a serial data message is sent to the appropriate door module to illuminate the indicator located in the outside rearview mirror.

Door Modules

The driver and passenger receive serial data messages from the side object sensors. When a message is received indicating that a vehicle or object is in the blind spot, the appropriate door module will apply voltage to the indicator located in the outside rearview mirror, illuminating the indicator. The door module provides a continuous low reference circuit for the indicator.

Outside Rearview Mirror

The outside rearview mirrors each contain an indicator that is controlled by the appropriate door module. This indicator is illuminated when a vehicle or object is position in the vehicle's blind spot.

Side Blind Zone Alert Operation

When the vehicle is started, the indicators located in the outside rearview mirror will briefly illuminate to indicate that the system is operating. The side object sensors cover a zone of approximately one lane over from both sides of the vehicle, 11 ft. or 3.5 m. This zone starts at each side mirror and goes back approximately 16 ft. (5.0 m). The height of the zone is approximately between 1.5 ft. (0.5 m) and 6 ft. (2.0 m) off the ground. When a vehicle or object is detected in this area, the appropriate indicator will be illuminated, indicating to the driver that it is unsafe to change lanes. If a turn signal is activated while the indicator is illuminated, the indicator will flash as a more urgent warning that a lane change may be unsafe.

Foul weather may affect the operation of the SBZA system. Occasional missed alerts can occur under normal circumstances and will increase in wet conditions. The number of missed alerts will increase with increased rainfall or road spray. Heavy rainfall, as well as mud, dirt, snow, ice, or slush build-up on the rear fascia, will completely disable the system.

If the vehicle is towing a trailer or has an object, such as a bicycle rack, attached to the rear of the vehicle, the SBZA system may not function properly and the indicators will remain illuminated at all time.

Side Blind Zone Alert DIC Messages

SIDE BLIND ZONE ALERT SYSTEM OFF

This message indicates that the system has been disabled through the DIC. Refer to the vehicle owners manual for instructions on how to set personalization options on the DIC.

SIDE BLIND ZONE SYSTEM UNAVAILABLE

This message indicates that the system has been disabled because the sensor is blocked or can otherwise not accurately detect vehicles or objects. Such instances may be mud, dirt, snow, ice, or slush build-up on the rear fascia, heavy rainfall, or excessive road spray.

SERVICE SIDE BLIND ZONE ALERT SYSTEM

This message indicates that the system requires service. When the message is displayed, the indicators will remain illuminated at all times, notifying the driver that the SBZA system should not be relied upon when changing lanes.

Object Detection Description and Operation Rear Parking Assist

The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicle's path when reversing at speeds of less than 8 km/h (5 mph). The distance and location of the object is determined by 4 object sensors located in the rear bumper. The parking assist system will notify the driver using the parking assist indicators and an audible signal through the radio.

The rear parking assist system is made up of the following components:

    • Object alarm module
    • Rear parking assist sensors
    • Parking assist indicator

Object Alarm Module

The object alarm module provides an 8-volt reference and a low reference to the four rear parking assist sensors. The object alarm module receives individual signals from each of the four sensors and determines the location and distance of an object based on these inputs. When an object is detected, the object alarm module will illuminate the appropriate LED on the parking assist indicator and send a serial data message to the radio requesting an audible alert.

Rear Parking Assist Sensor

The parking assist sensors are located the in rear bumper of the vehicle. The sensors are used to determine the distance between an object and the rear bumpers. Each sensor emits an ultrasonic frequency which is reflected off object located behind the vehicle. These reflections are received by the sensors. The time difference between when the frequency was emitted and when the reflection is received, known as sensor ring time, is used to determine the distance to the object. The sensors report this information to the object alarm module.

Parking Assist Indicator

The parking assist indicator is located in the interior rear of the vehicle and is visible through the inside rearview mirror. The indicator contains three LEDs: two amber and one red. The object alarm module controls these three LEDs as a visual indicator of how close the vehicle bumper is to an object. The object alarm module supplies voltage to each of the LEDs and commands each LED on by supplying an individual ground.

Rear Parking Assist Operation

When the vehicle is first placed into reverse, the rear parking assist system performs a bulb check. During the bulb check, the all three LED located in the parking assist indicator will illuminate for approximately 2 seconds to indicate that the system is working.

When backing up at speed of less than 8 km/h (5 mph), the system is constantly monitoring for object of interest located behind the vehicle. The rear parking assist system can detect objects greater than 7.6 cm (3 in) wide and 25.4 cm (10 in) tall. The system cannot detect objects below the bumper, underneath the vehicle. If an object is detected, one of the following will occur:

    • If the object is 1-2.5 m (40-96 in) away from the vehicle, the amber outside indicator will illuminate and a single chime will sound when the object is first detected.
    • If the object is 0.6-1.0 m (23-40 in) away from the vehicle, the amber outside and the amber middle indicators will illuminate.
    • If the object is 0.3-0.6 m (11-23 in) away from the vehicle, the amber outside, amber middle, and red outside indicators will illuminate.
    • If the object is less than 0.3 m (12 in) away from the vehicle, the amber outside, amber middle, and red outside indicators will flash and the chime sounds continuously.

If the rear parking assist system detects a malfunction, a DTC will be stored and the object alarm module will send a serial data message to the instrument panel cluster (IPC) to display the SERVICE PARK ASSIST message on the driver information center (DIC). A chime will sound and the red LED on the parking assist indicator will be illuminated. as a notification to the driver that a malfunction exists and the system is disabled.

Rear Parking Assist System DIC Messages

SERVICE PARK ASSIST

The driver information center (DIC) displays SERVICE PARK ASSIST when the object alarm module detects a malfunction in the rear parking assist system and the system is disabled. The DIC also displays SERVICE PARK ASSIST when a loss of communication occurs with the object alarm module.

PARK ASSIST OFF

The PARK ASSIST OFF message is displayed in the DIC when the object alarm system is disabled due to conditions that disable or inhibit the system. The red LED in the park assist indicator will be illuminated to indicate that the system has been disabled. The object alarm module requests the DIC display PARK ASSIST OFF when it detects that one of the following conditions:

    • The rear parking assist system is manually disabled using the driver information center (DIC).
    • The park brake is applied or not fully released.
    • An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, trailer hitch receiver, or tow bar.
    • The parking assist sensors are covered by snow, mud, dirt, slush, or ice.
    • The vehicle bumper is damaged.
    • Excessive paint thickness on a replacement parking assist sensor.
    • The parking assist sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.