For 1990-2009 cars

### Object Detection Description and Operation (Parking Assist)

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

### Object Detection Components

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

• | Object alarm module

• | Front object alarm sensors

• | Rear object alarm sensors

• | Parking assist switch

• | Parking assist switch indicator

• | Parking assist indicator in the instrument panel cluster

#### Object Alarm Module

The object alarm module provides an 8 V reference and a low reference to the eight object alarm sensors. The object alarm module receives individual signals from each of the eight sensors and determines the location and distance of an object based on these inputs. When an object is detected, the object alarm module will send a data message via CAN-Bus to the radio requesting an audible alert.

#### Object Alarm Sensors

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

#### Parking Assist Switch

The parking assist can be activated and deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

#### Parking Assist Switch Indicator

The indicator in the parking assist switch shows the status of the parking assist. If the lamp is ON, the parking assist is activated.

#### Parking Assist Indicator

The parking assist indicator in the instrument panel cluster is activated if the object detection detects a malfunction. If the indicator is ON, the parking assist is disabled.

### Parking Assist Operation

When an object is within the measuring range of the sensor, the ultrasonic pulse is reflected and is received by the sending or a neighboring sensor. The sensor converts this signal into a voltage signal and sends this signal to the object alarm module. The object alarm module evaluates the received sensor signals. As soon as an object is within the measuring range, the object alarm module sends a message via CAN-Bus to the radio in order to give out the acoustic distance signal. The measuring range is between 30-120 cm (11.81-47.24 inch). From a distance of 120 cm (47.24 inch), the acoustic signal is active. The frequency of the beep sound increases with decreasing distance. From a distance less than 30 cm (11.81 inch), the sound becomes continuous.

The parking assist can be activated and deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

The object alarm module carries out a self test and monitors the sensors for electrical and mechanical faults. Monitored is the power supply of each sensor and the sensor signals, which need to alter when the vehicle moves. If this is not the case, the sensor is acoustically blocked or faulty. Mud, ice and snow may cause obstruction of the function of the sensors. Besides that the object alarm module checks whether the correct type of sensor is installed. If any of these tests fails, a DTC with corresponding symptom is set, the parking assist is deactivated and the parking assist indicator in the instrument panel cluster is activated.