GM Service Manual Online
For 1990-2009 cars only

Object Detection Description and Operation Rear Parking Assist

Bumpers

The bumper systems are designed to sustain a collision into a fixed barrier at 8 km/h (5 mph) without damage. After absorbing the energy of a collision, the bumper systems restore themselves to their original positions. The bumpers feature an internal foam energy absorber and a polymer fascia cover.

Parking Assist System

Parking Assist System (PAS) is an electronic system designed to provide an acoustic tone informing the driver of obstacles at or near the rear of the vehicle during low speed manoeuvres such as parking. The PAS consists of four ultrasonic object sensor assemblies mounted to the rear bumper fascia, an electronic control module assembly mounted to the upside of wheelhouse panel and buzzer assembly mounted to the instrument panel. Sonar is used to detect the presence of obstacles within a defined area, by measuring the time between the transmission and reception of sound waves.

When reverse gear is selected, the sensors transmit short ultrasonic pulses and then listen for an echo reflected from an object within range. The electronic control module uses echo data from one or more sensors to calculate the distance to the obstacle.

Note: Some sound absorbing or reflecting materials can effect the range of detection. In extreme cases, temporary non-detection of obstacles can result.

System Operation

When the ignition is on and reverse gear is selected, a tone will sound from the buzzer for a period of 0.3 seconds to indicate system readiness.

The control module provides a voltage to each sensor sequentially which is converted into an ultrasonic pulse.

Where an object is within the detection range, the ultrasonic pulse is reflected (echoed) and received by the same and/or adjacent sensors.

The echoes are amplified, processed and returned to the control module as a digital signal. The control module processes this information and informs the driver of the object by activating an intermittent acoustic tone through the buzzer.

The four sensors are mounted onto the rear bumper fascia in an arrangement that provides a slight overlap of the polar patterns. This provides the best coverage of the detection area. The maximum detection distance is 150 cm.

The detection area is divided into four warning zones. As listed in the following table, the tone-on to tone-off period shortens as the distance to the detected object decreases.

Detection Zone

LC, RC (cm)

LM, RM (cm)

Tone ON

Tone OFF

1

20 ~ 30

20 ~ 30

Continuous

--

2

31 ~ 60

31 ~ 60

40 ms

280 ms

3

61 ~ 80

61 ~ 90

40 ms

480 ms

4

--

91 ~ 150

40 ms

680 ms

5

--

--

300 ms

--

Object Detection Description and Operation Rear Vision Camera

Rear Vision Camera System Operation

The object detection system can help a driver determine how close an object is to the rear bumper within a predefined rearward field of view. The system is composed of a video camera located on the liftgate outside handle, electrical harness, 7 inch LCD display integral to the instrument panel, TV tuner module and radio head unit. The object detection system can be operated by converting a gearshift to reverse in switch on state or pressing CAM button on Radio head unit (when the parking brake lever is pulled up on.)

Gear lever operates at reverse mode only (at this time is converted an image only to camera, function existing a voice) and then an image and a voice are return to the original function after reverse mode cancellation at the same time.

The following conditions may cause a degraded rear vision camera image:

    • Ice, snow, or mud has built up on the rear vision camera
    • Dark conditions
    • Extreme light conditions, such as glare from the sun or the headlights of another vehicle
    • Damage to the rear of the vehicle
    • Extreme high or low temperatures or extreme temperature changes

If a malfunction is detected in the system, Rear Vision Camera System Unavailable may be displayed on the navigation radio as an indicator to the customer that a problem exists that requires service.

Object Detection Description and Operation Holden Genuine Accessory

The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicle's path when reversing. The distance and location of the object is determined by object alarm sensors located in the rear bumper.

When the object detection system detects an object, the driver is notified through a series of buzzer sound from the object alarm indicators.

The rear object detection system is made up of the following components:

    • Object alarm module
    • Object alarm sensors
    • Object alarm indicator

Object Alarm Module

The object alarm module provides an 8-volt reference and a low reference to the object alarm sensors. The object alarm module receives individual signals from each of the object alarm sensors and determines the location and distance of an object based on these inputs. When an object is detected, the object alarm module activates the object alarm indicator.

Object Alarm 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.

Object Alarm Indicator

The object alarm module controls the buzzer sound produced by the object alarm indicator to indicate how close the vehicle rear bumper is to an object.

The object alarm indicator can be switched to the following settings:

    • HIGH
    • LOW
    • OFF

Rear Object Detection Distance and Buzzer Sounds

Distance M

Duration ON (MS)

Duration OFF(MS)

Less than 0.45

Continuous

--

0.45-0.90

75

75

0.90-1.50

75

150

Rear Object Detection Activation

To activate the object detection system the following criteria must be met:

    • Ignition is ON.
    • Reverse gear is selected.

To confirm the activation of the object detection system, two short buzzer sounds will be heard from the object alarm indicator.

Rear Object Detection System Deactivation

Automatic Deactivation

If the vehicle is fitted with a genuine Holden trailer harness, the rear object detection system is automatically disabled when the electrical connector of the trailer is connected to the vehicle.

Manual Deactivation

When towing trailers or caravans using non-compatible wiring harness; or when bike racks are fitted, the Rear Object Detection System can be manually deactivated by turning OFF the object alarm indicator switch.