When the rear parking assist system is activated, the system control module turns on the LED indicator in the switch button, turns on the sensors and issues a command to emit a single sound signal confirming the activation of the system. If an object appears within the sensor's range, then with the system on, a sequence of warning sounds is immediately emitted.
If the parking assistance system is not required, it can be temporarily deactivated by pressing the switch. For vehicles with rear sensors only, the system can be reactivated by pressing the switch again or by turning the ignition off and on again. The system will then be automatically activated when reverse gear is selected. The system remains active when shifting from reverse to neutral. This takes into account the likelihood that the driver will continue (in any way) move the car backwards with the gearbox in neutral.
When a trailer is connected, the parking assistance module receives a signal via the CAN bus from the central electrical distribution box. Upon receiving this signal, the parking assistance control module suspends the system.
On vehicles equipped with front and rear sensors, the parking assistance system is automatically activated when the ignition is turned on. (position II), the selector lever is not in the Park position and the electronic parking brake is released. At speeds above 10 km/h, the front parking aid is deactivated. When the speed drops to 6 km/h, the front parking aid is resumed. If the electronic parking brake (EPB) is applied or the selector lever is moved to the Park position, the parking aid is deactivated.
Operation of sensors
The parking assistance module analyzes the data received from the sensors to detect obstacles in the sensor's field of view. If no obstacles are detected, the parking assistance system does not emit any audible signals. If an obstacle is detected, the parking assistance speaker emits a series of audible signals.
The maximum obstacle detection distance is 1800 mm. When an obstacle is detected, the interval between the sound signals decreases as you approach it, and at a distance of approximately 350 mm from the obstacle the sound signal becomes continuous.
If, from the moment an obstacle is detected, the distance between the obstacle and the central sensors does not decrease further, the interval between the sound signals does not change. If an object is detected by only one extreme sensor, the warning signal will stop after 5 seconds, unless the distance from the object to the extreme sensor changes.
Detection Zone
| Item name | Spare part catalog number | Description |
| A | - | Intermittent warning sound |
| B | - | Continuous warning sound |
Detecting an obstacle and calculating the distance to it
When operating in a combined transmit/receive mode, the sensor emits ultrasonic pulses and receives signals reflected from an obstacle. The parking assistance control module amplifies the reflected signals and compares them with the threshold values programmed in the program to calculate the distance. This is achieved by determining the time elapsed between the transmission and reception of the ultrasonic signal.
When the sensor operates in the receiving mode, it receives the radiation signals of the neighboring sensor. This mode is used to improve the accuracy of the system.
The obstacle detection cycle consists of transmitting and receiving a series of pulses by one sensor operating in combined mode on commands from the parking assistance control module. The computer then switches this and the adjacent sensors to the mode of receiving only the reflected signal. After a short pause, the operation is repeated, but now the next sensor operates in combined mode. The cycle continues until all 4 sensors emit ultrasonic signals. This takes about 100 milliseconds. The control module performs several measurements of the signals of the same sensor to eliminate random errors in the calculations.
If the object is located directly opposite the sensor, the distance is calculated based on the time between the transmission and reception of the signal. If the obstacle is located between two sensors, the control module calculates the distance based on the signals from the two sensors, solving the triangulation problem.
To solve the triangulation problem, the control module must know the distance between the individual sensors in the bumper. This information is stored in the control module's memory. Knowing the distances from each sensor to the obstacle and the distance between adjacent sensors, the control module can calculate the minimum distance from the car's bumper to the obstacle.
When the car approaches several obstacles at the same time, the control module determines the distance to the nearest one.
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