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Rear outer parking aid sensor
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Rear outer parking aid sensor holder
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Front parking aid speaker
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Front inner parking aid sensor holder
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Front inner parking aid sensor
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Front outer parking aid sensor holder
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Front outer parking aid sensor
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Parking aid switch (with light emitting diode (LED))
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Parking aid module (with rear parking aid speaker)
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Rear inner parking aid sensor
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Rear inner parking aid sensor holder
Description and operation
Only one level of parking aid system is installed to the vehicle, a front and rear system.
The parking aid system provides an audible warning to the driver when any obstacles are in the path of the vehicle during forward or reverse parking manoeuvres. The system consists of four ultrasonic parking aid sensors in each bumper, a parking aid module, parking aid speaker(s) and a parking aid switch.
At low speeds, the parking aid module uses the parking aid sensors to monitor the area around the front and rear bumpers. If an object is detected within a monitored area, the parking aid module outputs a warning tone using the parking aid speakers. Objects very close to the ground may not be detected, but because of their low height will not cause damage to the vehicle.
The parking aid module communicates through discrete signals with the parking aid speakers. The parking aid speakers output the applicable warning tones when an object is detected. The medium speed controller area network (CAN) bus is used to collect vehicle data from other vehicle systems.
When the parking aid module activates the system, the parking aid switch LED is illuminated. The parking aid module processes signals received from the sensors to determine if there is an object within the detection range of the parking aid sensors.
In the combined mode, the parking aid sensor(s) emit a series of ultrasonic impulses and switch to receiver mode to receive the echo reflected by an obstacle within the detection range. The received echo signals are amplified and converted from an analogue signal to a digital signal by the sensor. The digital signal is passed to the parking aid module and compared with pre-programmed data stored in an EEPROM within the parking aid module. The parking aid module receives this data through the signal line from the parking aid sensor and calculates the distance from the object using the elapsed time between the transmitted and received impulse. The duration of the impulse duration is determined by the parking aid module, with the parking aid sensor controlling the frequency of the impulse output.
In receiver mode, the parking aid sensor receives impulses that were emitted by adjacent parking aid sensors. The parking aid module uses this information to determine the distance of the object.
If no objects are detected there are no further warning tones. If an object is detected, repeated audible tones are emitted from either parking aid speaker(s) as appropriate. The time delay between the tones decreases as the distance between the object and the vehicle decreases, until at approximately 250 mm (10 inches), the audible tone becomes continuous.
If, after the initial detection of an object, there is no decrease in distance between the object and the vehicle, the audible warning tones remain constant if the object is detected by a central parking aid sensor or stops after 3 seconds if the object is detected by a corner parking aid sensor.
The parking aid module continues to monitor the distance and will resume the warning tones if a decrease in distance is detected.
The parking aid system is activated when the driver presses the parking aid switch (vehicle speed below 16 km/h (10 mph) and the parking aid system not active) or selects reverse gear.
Front and rear parking aid sensors are activated and deactived together.
The parking aid system operation is disabled when the parking aid switch is pressed while the parking aid system is active or the ignition is switched off. The parking aid system operation is also disabled if the vehicle forward speed exceeds 16 km/h (10 mph).
The parking aid system can detect when a trailer is connected to the vehicle by a message output on the medium speed CAN bus from the trailer. When the parking aid module detects that a trailer is connected to the vehicle, the rear parking aid sensors are disabled to prevent constant warnings due to the close proximity of the trailer.
Front parking aid speaker
The parking aid module has three connectors which provide for power, ground and CAN bus connections, front and rear parking aid sensors, parking aid switch, LED and parking aid speakers.
The medium speed CAN bus connections provide for the receipt of the following information from other systems:
- ABS (anti-lock brake system) module - Road speed signal
- Central junction box (CJB) - Reverse gear engaged signal, vehicle configuration parameters, carmode and powermode
- Powertrain control module (PCM) - Vehicle speed signal
- Transmission control unit - Gear lever position (automatic transmission)
- Trailer module - Trailer connection status
The parking aid module carrys out self-check routines and when the parking aid system is active, checks the parking aid sensor wiring for short or open circuits. If a concern is detected, a diagnostic trouble code (DTC) is stored in a memory in the parking aid module and the front and rear parking aid sensors will be disabled until the DTC is cleared and the ignition cycled. The driver is made aware of any concern condition by the parking aid switch LED flashing and a continuous warning tone being emitted for 3 seconds at the start of ignition cycle, in place of the normal short tones when the parking aid system is functioning normally. DTCs can be read using the worldwide diagnosis system (WDS) through the data link connector (DLC).
In addition, the rear parking aid speaker is integrated to the parking aid module housing.
Rear parking aid sensor
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Rear outer parking aid sensor(s)
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Rear inner parking aid sensor(s)
The parking aid sensor comprises of a sensor and a holder. The holder makes sure that each parking aid sensor is correctly orientated in relation to its location in the rear bumper.
Each parking aid sensor has a three pin connector which connects with the rear bumper wiring harness, which in turn is connected to the main body wiring harness. Three pins provide for power supply, ground and signal lines to and from the parking aid module.
Each parking aid sensor comprises of the following:
- a plastic housing
- an aluminium membrane which contains a piezo electric disc
- a decoupling ring which may be a separate component from the sensor or overmoulded to the sensor membrane
The disc resonates at a frequency of ca. 50kHz, producing the ultrasonic output. The disc also receives the reflected echo signal from any objects within range.
The parking aid module controls the operation of each parking aid sensor using a digital output on the signal line. The parking aid module controls the parking aid sensor in one of two modes; combined transmitter and receiver mode or receiver mode only.
Parking aid switch
The parking aid switch is located in the instrument panel, above the audio unit or navigation system display module. The parking aid switch is the left-hand side switch with an integral LED.
The parking aid switch is a non-latching push switch which allows the driver to select the parking aid system on or off. When pressed, the parking aid switch momentarily connects a ground to the parking aid module. The LED indicates when the parking aid system is active. The LED is controlled by the parking aid module.
The parking aid switch allows the driver to disable the parking aid system when reverse gear is selected or to activate the parking aid sensors when not in reverse gear.
If a concern exists in the parking aid system, the LED flashes for 3 seconds when the reverse gear is selected or the driver selects the parking aid sensors on, using the parking aid switch.
Front parking aid sensor
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Front inner parking aid sensor(s)
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Front outer parking aid sensor(s)
The parking aid sensor comprises of a sensor and a holder. The holder makes sure that each parking aid sensor is correctly orientated in relation to its location in the front bumper.
Each parking aid sensor has a three pin connector which connects with the front bumper wiring harness, which in turn is connected to the main body wiring harness. Three pins provide for power supply, ground and signal lines to and from the parking aid module.
Each parking aid sensor comprises of the following:
- a plastic housing
- an aluminium membrane which contains a piezo electric disc
- a decoupling ring which may be a separate component from the sensor or overmoulded to the sensor membrane
The disc resonates at a frequency of ca. 50kHz, producing the ultrasonic output. The disc also receives the reflected echo signal from any objects within range.
The parking aid module controls the operation of each parking aid sensor using a digital output on the signal line. The parking aid module controls the parking aid sensor in one of two modes; combined transmitter and receiver mode or receiver mode only.
Distance calculation
Front parking aid sensors
