general description systems
PRE-SAFE system(preventive passenger safety system) includes the following functions:
* Reversible seat belt tensioner for driver and front passenger
*Setting the front passenger seat position
* Automatic closing of the sliding/tilting sunroof (SHD).
The PRE-SAFE system is activated in critical driving situations (forward driving), in a situation that could potentially result in an accident. The functions that are activated actually before a crash (see list of functions above) are intended to create optimal conditions before an expected collision.
The following control units and elements are active participants in the functioning of the system:
* ARCADE Airbag passenger restraint system control unit (N2/11)
* Block ESP control(N30/4)
* Reversible driver's seat belt tensioner (A76)
* Reversible front passenger seat belt tensioner (A76/1)
System operation
Conditions for system operation
* Terminal 15 "ON"
* Vehicle speed v > 30 km/h and vehicle movement forward
Critical vehicle driving conditions in which the PRE-SAFE system is activated:
* Emergency braking, in which the brake assist system (BAS) is activated
* Oversteer (Querdynamik) is determined by: steering angle, skid angle, lateral acceleration, wheel speed
* Understeer (Querdynamik) is determined by: steering angle, skid angle, lateral acceleration, wheel speed
Note:
* The critical driving condition of the vehicle is taken into account when driving forward and in reverse.
*Information" Reverse gear ON" is sent electronic module gear selection EWM (N15/5).
The PRE-SAFE activation logic is integrated into both reversible seat belt tensioners (A76, A76/1), i.e. both reversible belt tensioners receive and transmit the same signals via the transmission bus CAN-C data, which are necessary for the operation and implementation of the functions of the PRE-SAFE system. Depending on what situation is recognized by the PRE-SAFE system, emergency braking(Langsdynamik) or car skidding (Querdynamik), the operating mode of the reversible front left/front right seat belt tensioners (A76, A76/1) differs.
Emergency braking (longitudinal dynamics)
The data transmitted by the ESP control unit (N30/4) commands the front left/front right reversible seat belt tensioners (A76, A76/1) to perform the corresponding functions of the PRE-SAFE system:
1. Seat belt tension
Prerequisites:
* Both driver/front passenger seat belts are fastened
* The front passenger seat is recognized as occupied (signal via CAN-C data bus from the ARCADE Airbag control unit (N2/11)).
2. Preparing the front passenger seat for possible movements
The following seat settings must be standardized:
Longitudinal and level installation
Seat backrest tilt
The front left/right reversible seat belt tensioners (A76, A76/1) cyclically send readiness information via the CAN-C data bus to the central interface ZGW (N93), and from it via the CAN-B data bus to the front seat control unit passenger with memory function (N32/2)
Only if the front passenger seat is not in the optimal position (from a collision point of view) and is recognized as occupied (signal via CAN-C data bus from the Airbag ARCADE control unit (N2/11)), the seat is adjusted to the optimal position. position in accordance with the PRE-SAFE situation.
This automatic installation The front passenger seat can be interrupted at any time by pressing the seat adjustment buttons.
The seat does not return to its original position after the PRE-SAFE situation has ended.
When the PRE-SAFE system is activated, following settings in seat position:
If passengers are buckled up (seat belt buckle is fastened):
* If the seatback angle is greater than 28° from the forward extreme position, the seatback moves to the upright position. If the tilt angle is less than 28°, then no settings are made.
* The front seat cushion angle is set to the middle position. If the front of the cushion is raised high, no changes are made.
* If the seat is moved too far forward, it moves back 100 mm from its forward position. If, on the contrary, it is moved very far back, it moves forward 50 mm from the rearmost position.
If passengers are not fastened (the seat belt buckle is not fastened):
* If the seatback angle is greater than 20° from the forward extreme position, the seatback moves to the upright position. If the tilt angle is less than 20°, then no settings are made.
* The seat cushion at the front is raised to its fullest position.
* The seat lowers to its lowest position.
* If the seat is moved very far back, it moves forward 100 mm from the rearmost position. Note:
* Any installations or movements of the front passenger head restraint related to the operation of the PRE-SAFE system are not provided.
* The operation of the PRE-SAFE system, namely its effect on the front passenger seat, can be switched off using Star-Diagnose in the settings of the front passenger seat control unit (N32/2).
* For the driver's seat, any installations and movements related to the operation of the PRE-SAFE system are not provided.
Vehicle lateral acceleration (Querdynamik)
1. Seat belt tension: (see emergency braking)
2. Preparing the front passenger seat for possible movements: (see emergency braking)
3. Closing the sunroof (SHD): signals from the ESP control unit (N30/4) and the steering column module (N80) trigger the PRE-SAFE system, namely the reversible seat belt tensioners (front left/front right (A76 , A76/1), sliding/tilting sunroof (SHD) closes
The overhead control panel DBE (N70) automatically closes the sliding sunroof (SHD) after receiving a “command” from the PRE-SAFE system via the CAN-B data bus via the central interface ZGW (N93). This function can be canceled at any time by operating the sunroof control switch (N70s1). If the DBE control unit (N70) continues to receive information that the PRE-SAFE system has been activated, the sunroof closing process is resumed. The tilt/slide sunroof does not return to its original position after the PRE-SAFE system has been activated.
Note:
When closing the hatch, the anti-pinch protection operates. When an obstacle is detected, the sunroof drive switches to reverse movement. For optionally installed sliding glass roof(on type W251) the PRE-SAFE system is not available.
End of operation of the PRE-SAFE system
The reversible seat belt tensioners front left/front right (A76, A76/1) set the control signal via the CAN-C data bus to a passive level if a situation involving activation of the PRE-SAFE system is no longer recognized.
Accordingly, if the adjustment of the front passenger seat position is interrupted by the passenger seat control unit (N32/2), with memory, although the optimal position for the PRE-SAFE system has not yet been achieved. If the vehicle's acceleration reaches a value less than 0.3 g (negative acceleration), the reversible front left/front right seat belt tensioners (A76, A76/1) loosen the additionally tensioned driver and front passenger seat belts. If the first step of loosening the seat belts is not completed successfully, a second attempt to loosen the seat belts is initiated. The automatic closing of the sliding/tilting sunroof (SHD) is not interrupted after the PRE-SAFE system has finished operating.
The front passenger seat and sliding/tilt sunroof (SHD) will not return to their original position after the PRE-SAFE situation has ended.
Heavy traffic on busy highways is in itself very unsafe and if something happens, seconds count. It is these seconds that determine the ending of someone’s life. While driving on the highway, the driver must be measured and attentive, and under no circumstances be distracted by trifles. The driver can always think and take his mind off the road, and this leads to an inevitable collision; the Pre-Safe system is designed to prevent or minimize harm from a possible collision.
When this system was tested on car stimulators, 70 ordinary invited German drivers were offered to accelerate to 80 km in an ordinary suburban road and just go. After the driver had more or less adapted to this driving style, in order to distract him from the road, he was shown that a disaster had occurred on the road on the side of his car: cars with police officers, a certain number of people on the side of the road - all this distracted the attention of the majority. The test drivers were so distracted that they did not react to any signs given by the car equipped with the Pre-Safe system, eventually triggering critical braking, which reduces the speed by 10 km, but still, with all this, the force of a possible collision is miniaturized by 40%.
This system uses radar technology to recognize danger on the road and notify the driver about it. These particular radar technologies have undergone unprecedented tests (cars equipped with the Pre-Safe system drove about 1 million km on ordinary roads before entering serial production). This system was also tested on autosimulators and test sites. It's no secret that preventing accidents is one of the priorities for any self-respecting automaker, so Mercedes-Benz is far from being the first in this case.
The Pre-Safe system is designed to save the life of the driver and not only him; it was developed by Mercedes-Benz. A car equipped with such a system lets the driver know visually and audibly about a critical approach to another car and the possibility of a collision; if the driver does not react to this, then the car itself automatic mode includes partial braking (40% of the vehicle's braking force is applied 2.6 seconds before the expected collision).
This system scans all movement within the radius of the car, it gives the driver several chances to react correctly and change the situation by braking on time. At the same time, the driver and the passenger sitting next to them have their belts tightened, and airbags are inflated in the multi-profile seats, while the body position of the passengers and the driver is fixed, everything is made so that the body of the driver and passenger takes the most non-dangerous position that minimizes damage during a possible accident.
Just a little more than 1 second before the collision, a car equipped with such a system begins to brake automatically, while the speed of the car, which is moving towards a collision, is not very significant, but is still reduced, and this in turn minimizes the force of the impact.
If the driver reacts to the car’s comments, the latter, using a certain system, helps him slow down, and the braking force increases. It should be noted that before the introduction of this system, Mercedes-Benz cars were equipped en masse with other security systems, which, in cooperation with Pre-Safe, increased the safety of the car itself.
The Pre-Safe system, in combination with other systems from Mercedes-Benz, significantly minimizes harm during an accident or helps prevent it. Typically, 70% of drivers react to the signs given by a car equipped with the Pre-Safe system, but the other 30% do not react and a collision still becomes inevitable.
Yellow warning light is on warning light. Electric parking brakefaulty
Turn off the ignition. Press and hold the electric parking brake for at least ten seconds. engage first gear. shift the gearbox to position "P".
Contact a qualified specialist workshop. Yellow warning light and red warning lamp are burning. The electric parking brake is faulty. Release the electric parking brake manually. Or:.
Cars with
automatic transmission
gears:
more
gears:
If the electric parking brake is not allowed to continue driving.
Contact a qualified specialist workshop. The red indicator light flashes and the yellow warning light lights up.
The electric parking brake is faulty. Release the electric parking brake manually. Or:.warning lamp Turn the ignition off and on again. The electric parking brake is faulty. Release the electric parking brake manually. Apply the electric parking brake manually. shift the gearbox to position "P".
Turn the front wheels toward the sidewalk curb.
Contact a qualified specialist workshop. The yellow warning light is on.
The red warning lamp flashes for approximately ten seconds after the electric parking brake is applied or released. After this, the lamp goes out or remains on. The electric parking brake is faulty. Turn the ignition off and on again.
Apply the electric parking brake.Vehicles with manual transmission: engage first gear. shift the gearbox to position "P".
Contact a qualified specialist workshop. If the electric parking brake does not Release the electric parking brake manually. Or:.Vehicles with manual transmission (with automatic emergency release):
insert the seat belt into the seat belt buckle and press the accelerator pedal harder when driving away.
Cars with automatic transmission: Turn the ignition off and on again.
Contact a qualified specialist workshop. release the electric parking brake automatically
