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Mercedes Benz 169 - 245 Active Park Assist

The whole System
The whole System
Ultrasonic sensors
Ultrasonic sensors
Block Diagram
Block Diagram
System in general
With the model refinement of the A-Class and B-Class, Active Park Assist, code (235), is available as special equipment for the first time and the PARKTRONIC (PTS) system is included additionally.
Like the familiar PARKTRONIC system, Active Park Assist operates using ultrasonic sensors.
Active Park Assist helps the driver to find a sufficiently large parallel parking space and then park the vehicle comfortably in the space.
Ultrasonic sensors are used to scan the road for parallel parking spaces, which are then suggested to the driver. Once a parking space has been found, the system controls the steering maneuver by actuating the electric steering actuator.
The driver remains responsible for determining the acceptability/plausibility of the parking space found by the system and also controls the longitudinal movement of the vehicle via the accelerator pedal and brake pedal.
Ultrasonic sensors
On vehicles with Active Park Assist, the outer left and right front ultrasonic sensors are not just used for the PARKTRONIC function, they also scan the road for potential parallel parking spaces. The two outer sensors therefore change their sensing range according to requirements.
· B8/1 Outer left front PTS ultrasonic sensor
· B8/2 Center left front PTS ultrasonic sensor
· B8/3 Inner left front PTS ultrasonic sensor
Function sequence
The Active Park Assist function does not have to be activated. At vehicle speeds of up to 35 km/h, the outer ultrasonic sensors in the front bumper always operate in the background to scan the road for parking spaces on both sides, to the left and right of the vehicle. The parking spaces that are found are stored over a distance of approx. 15 m.
At low speeds, the symbol "P" is displayed on the multifunction display of the instrument cluster to indicate that the system is searching for parking spaces.
When a parking space is found, an arrow indicates the side of the road on which the parking space is located.
By default the system only indicates parking spaces on the passenger-side of the vehicle. To have parking spaces on the driver side indicated as well (e.g. on one-way streets), the driver must actuate the turn signal towards the driver side.
The Active Park Assist function detects parallel parking spaces based on the following criteria:
The space must be parallel to the road, must be at least 1.3 m longer than the vehicle, may not be longer than 10 m and must be at least 1.5 m wide.
The system only detects free spaces based on whether the vehicle would fit in the space. It cannot detect whether or not the free space is actually a parking space.
If the driver stops and engages the reverse gear after driving past a suitable parking space, the following message is first displayed on the multifunction display of the instrument cluster:
• "Activate Park Assist?"
"Pay attention to your surroundings"
Confirm with "Yes" or "No" using the buttons on the multi function steering wheel
The parking maneuver supported by the Active Park Assist function is started once the system warning messages have been confirmed on the instrument cluster.
The following message appears next:
• "Park Assist active"
"Accelerate and brake yourself"
The driver now removes his/her hands from the steering wheel and only has to carefully actuate the accelerator and brake pedals until the final position is reached. Additional maneuvering may be required.
The following message then appears:
• "Parking assistance complete"
"Take over control"
The Active Park Assist function is aborted if the vehicle speed exceeds 10 km/h during parking or if the driver intervenes in the steering maneuver while the vehicle is being parked.
The lateral boundary of the parking space (width) is determined based on a detected obstacle (e.g. a curb). If no obstacle is detected at the side, the vehicle is aligned based on the obstacle in front (vehicle). In this case, the parking angle is determined by the direction of travel as the vehicle moved past the parking space.
While maneuvering, the multifunction display displays one of the following instructions to the driver, if necessary:
• "Please engage forward gear"
• "Please engage reverse gear"
ControlUnits in Block Diagram
· A1 Instrument cluster
· A44/1 Driver side instrument panel PTS warning indicator
· A44/3 Rear dome lamp PTS warning indicator
· A91 Electromechanical controller unit (ES)
· B8/1 Outer left front PTS ultrasonic sensor
· B8/2 Center left front PTS ultrasonic sensor
· B8/3 Inner left front PTS ultrasonic sensor
· B8/4 Inner right front PTS ultrasonic sensor
· B8/5 Center right front PTS ultrasonic sensor
· B8/6 Outer right front PTS ultrasonic sensor
· B8/7 Outer right rear PTS ultrasonic sensor
· B8/8 Inner right rear PTS ultrasonic sensor
· B8/9 Inner left rear PTS ultrasonic sensor
· B8/10 Outer left rear PTS ultrasonic sensor
· B38/2 Rain/light sensor (with code (U58) Exterior light & vision package)
· L6/1 Left front rpm sensor
· L6/2 Right front rpm sensor
· L6/3 Left rear rpm sensor
· L6/4 Right rear rpm sensor
· N10 SAM control unit
· N15/5 Electronic selector lever module control unit (with transmission 722)
· N18 HEAT [HAU] control and operating unit (without code (580) Automatic air conditioning and without code (581) Comfort automatic air conditioning)
· N22 AAC [KLA] control and operating unit (with code (580) Automatic air conditioning)
· N22/7 Comfort AAC [KLA] control and operating unit (with code (581) Comfort automatic air conditioning)
· N28/3 Trailer control unit (with code (550) Trailer hitch)
· N47-5 ESP and BAS control unit
· N62 PTS control unit
· N68 Electrical power steering (ES) control unit
· N70 Overhead control panel control unit
· N72/1 Upper control panel control unit
· N72/1s8 PTS OFF switch
· N73 EZS control unit
· N80 Steering column module
· S1 Rotary light switch
· S12 Parking brake indicator switch
· S16/2 Backup light switch (with transmission 711, 716)
· CAN B Interior CAN
· CAN C Engine compartment CAN
· LIN B8 Climate control LIN

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