GM Service Manual Online
For 1990-2009 cars only

Object Detection Description and Operation Parking Assist

The object alarm system monitors the distance and how close a vehicle is to an object when backing up in a parking maneuver. The object alarm system will notify the driver of any objects of interest when backing up at speeds less than 5 km/h (3 mph). The distance between a vehicle and an object of interest is monitored by the 4 ultrasonic sensors located in the rear bumpers of the vehicle. The object sensors receive the echo signals reflected off an object of interest while the vehicle is backing up at speeds less than 5 km/h (3 mph). The rear object sensor control module receives the vehicle speed input from the ECM via the vehicle speed signal circuit. When the backing up speed exceeds 5 km/h (3 mph), the rear parking assist (RPA) system is disabled. The object detection system uses visual displays and audible warnings from the radio speakers to warn the driver of an object of interest within the defined field of view. The rear integration module (RIM) controls the RPA chime function via the chime control circuit and will send serial data request to the radio to sound the chime as needed. The visual RPA display comprises of two amber and one red indicators and these indicators illuminate based on the vehicle distance to the object of interest. When the RPA system is activated the RPA display first performs a bulb check before any normal operation. The object sensor is a three wire sensor comprising of the supply voltage circuit, signal circuit and the low reference circuit. Power and ground is provided to the object sensors from the rear object sensor control module via the object sensor supply voltage circuit and low reference circuit. The typical object sensor signal circuit voltage when the system is active is between 7.2-9.2V. The object detection system is initiated when the rear object sensor control module receives the transmission reverse input from the RIM via the backup lamp supply voltage circuit.

When the ignition is ON and the vehicle is placed into reverse, the RPA performs a bulb check. During the bulb check, the 3 indicators on the display illuminate for approximately 2 seconds to indicate that the system is working. The RPA performs a bulb check and operates when the following conditions are present:

    • The ignition is ON.
    • The vehicle is placed in REVERSE (R).
    • The vehicle speed is less than 5 km/h (3 mph).
        At speeds greater than 5 km/h (3 mph), the RPA is disable. The red indicator flashes to warn the driver that the RPA is disabled.

The RPA senses how close the vehicle is to an object. The distance is determined by the 4 ultrasonic sensors located on the rear bumper. When the system detects an object, one of the following will occur:

    • If the object is less than 0.3 m (11 in) away from the rear of the vehicle, the amber outside, amber middle, and the red outside indicators flash and the chime sounds continuously.
    • If the object is less than 0.3-0.5 m (11-20 in) away from the rear of the vehicle, the amber outside, amber middle, and the red outside indicators are on and the chime sounds continuously.
    • If the object is 0.5-1.0 m (20-40 in) away from the rear of the vehicle, the amber outside, and the amber middle indicators are on.
    • If the object is 1.0-1.5 m (40-60 in) away from the rear of the vehicle, the amber outside indicator is on and the chime sounds one time on the first detection of an object.

The RPA can detect objects 7.6 cm (3 in) wide and at least 25.4 cm (10 in) tall. It cannot detect objects above the level of the roof.

If the red indicator flashes continuously, the on-board diagnostic needs to be entered to determine if a malfunction is present. Refer to Diagnostic Trouble Code (DTC) Displaying.

Object Detection Description and Operation Lane Departure Warning

Vehicle direction alert alarm warning (VDAAW) is a convenience feature that issues a warning when the system detects that the vehicle has unintentionally crossed a lane marking. The VDAAW lane sense function utilizes imagery collected by the camera to detect lane markings. An audible warning provided by the audio system is issued when then VDAAW system detects an unintentional lane departure. The VDAAW receives vehicle speed, steering wheel angle and brake pedal position information via the serial data circuit. The VDAAW system consists of two main components:

    • The VDAAW module which includes the camera
    • VDAAW enable/disable (ON/OFF) switch

The VDAAW enable/disable switch is a soft key located in the navigation radio system. The VDAAW module receives the VDAAW switch inputs from the navigation radio via serial data circuit. The VDAAW system remembers the last switch state (ON or OFF) and returns to the last switch state in the next ignition cycle.

The VDAAW module is mounted on the front windshield and uses a forward facing camera to determine lane markings. It is important that the windshield in front of the camera remain clean. Fog on the windshield or the camera lens may inhibit proper operation.

The VDAAW system has four operating states:

OFF: The VDAAW system is turned OFF and the ignition is OFF.

Disabled: The system is disabled by the operator from the VDAAW disable switch.

Not Ready To Assist (NRTA): The system is enabled, but unable and not ready to detect lane crossings for any of the following reasons.

    • Vehicle speed is less than 35 mph. The VDAAW system is designed to function at speeds greater than 35 mph.
    • The VDAAW system cannot detect lane markings. This may be because there are no lane markings (as in a country road) or that the lane markings cannot be determined because of snow or other elements that may affect driving conditions.
    • The windshield or camera lens may be blocked by fog or other elements and the system cannot detect lane markings
Ready To Assist (RTA): The system is enabled and ready to warn of unintentional lane crossings. The VDAAW ready to assist state is indicated by a green indicator in the instrument panel cluster.

Lane Crossing Alerts

A lane crossing alert consists of the following:

    • Chimes are activated through the vehicle audio system.
    • The VDAAW indicator that is normally green will turn to flashing amber.

The VDAAW system will not give any lane crossing alerts under the following conditions:

    • Vehicle speed is less than 35 mph.
    • The system cannot detect lane markings.
    • The correct turn signal is activated. An activated turn signal is interpreted as an intentional lane crossing.

VDAAW DIC Messages

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

    • SERVICE LANE DEPARTURE SYSTEM
    • LANE DEPARTURE SYSTEM UNAVAILABLE

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.