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Home >> Mercedes Benz >> 2017 >> CLS400 Base >> Repair and Diagnosis >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> Throttle Control, Speed Control Systems - 218 Chassis >> Basic Knowledge >> DISTRONIC PLUS INCL. BAS PLUS and PRE-SAFE® Brake, Function - GF30.30-P-0006FQ

DISTRONIC PLUS INCL. BAS PLUS and PRE-SAFE® Brake, Function - GF30.30-P-0006FQ

MODEL 218 

up to year 2015 

with CODE 233 (DISTRONIC PLUS) 

up to 28.02.2013 

G12623123Courtesy of MERCEDES-BENZ USA

As of 01.03.2013 

G12623124Courtesy of MERCEDES-BENZ USA

Function requirements, general 

IMPORTANT The standstill coordinator function is described in detail in the separate function description "Adaptive Brake (ABR) function".

DISTRONIC PLUS incl. BAS PLUS and PRE-SAFE® brake, general points 

IMPORTANT The units and values for the speed shown in the following text should be assigned to the possible national versions. The details in "miles per hour (mph)" refer to vehicles with a miles indicator.

The DISTRONIC PLUS automatically regulates the speed and the distance to the vehicle driving immediately ahead in a vehicle speed range of v = 0 to 200 km/h and from v = 200 to 0 km/h (v = 0 to 120 mph and from v = 120 to 0 mph) according to the request from the driver. The PRE-SAFE® brake function permanently determines the potential danger of a rear-end collision occurring and initiates appropriate measures to mitigate the effects of a collision in critical situations. Furthermore, there is a distance warning function contained therein which advises the driver about a vehicle driving immediately ahead which is too close. An optical and acoustic warning is issued before any possible collisions with vehicles or stationary obstacles on the vehicle's own lane.

If the driver reacts to the warning with emergency braking, he is supported by the Brake Assist System (BAS) PLUS function. The required brake boosting effect for this is calculated according to the situation. This means that the brakes are automatically applied as intensively as required (max. approx. a = 10 m/s2 ). In doing this the threat of a collision can be reduced or at least the severity of the accident can be reduced.

If the driver does not react to the warning, the PRE-SAFE® brake function brakes vehicle autonomously and can then mitigate the effects of a possible collision.

IMPORTANT The PRE-SAFE® brake feature also supports the PRE-SAFE® safety concept. The PRE-SAFE® function is described in detail in a separate function description.

IMPORTANT The following subfunctions of DISTRONIC PLUS are described in a separate function description:

The following graphical representations show the principle of operation of the functions DISTRONIC PLUS incl. BAS PLUS and PRE-SAFE® brake.

Detection area of the radar sensor system 

G12623125Courtesy of MERCEDES-BENZ USA

Illustration of the principle of the functions BAS PLUS and PRE-SAFE® brake, shown on model 221 

G12623126Courtesy of MERCEDES-BENZ USA

Operation of the DISTRONIC PLUS takes place over the cruise control lever.

Design of the cruise control lever 

G12623127Courtesy of MERCEDES-BENZ USA

Operation over the CC lever, vehicle without code 494 (USA version) 

G12623128Courtesy of MERCEDES-BENZ USA

Operation over the CC lever, vehicle with code 494 (USA version) 

G12623129Courtesy of MERCEDES-BENZ USA

IMPORTANT The distance to the vehicle driving immediately ahead is displayed in the multifunction display for t = 5 s after actuation of the CC lever.

Through selection of the operating level "DISTRONIC PLUS" in the menu "Assistance" the distance graphic is shown permanently. Display of the distance graphic can be switched on or off independently of the activity of the automatic distance control. The distance to the vehicle driving immediately ahead can be set over the DISTRONIC control in seven stages between t = 1.0 and 2.0 s. If, for example, a distance of t = 2.0 s is set, the vehicle driving immediately ahead will be followed at a temporal distance of t = 2.0 s.

The control takes place by the video and radar sensor system control unit. The video and radar sensor system control unit intervenes actively in the engine management as well as in the brake system to implement the functions. The acoustic warnings are emitted by the warning buzzer in the IC. The optical note and warning messages are issued over the multifunction display.

The video and radar sensor system control unit evaluates the input factors and transmits an appropriate request for controlling of the functions DISTRONIC PLUS, BAS PLUS and PRE-SAFE® brake via the following CAN:

The video and radar sensor system control unit evaluates the following input factors:

Operating condition for engine/drivetrain:

The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or the "Drivetrain operational" signal via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

Engaged gear range:

Information about the engaged gear range is sent by the fully integrated transmission control unit via the drive train CAN, CDI control unit or the ME-SFI [ME] control unit and chassis CAN 1 (from 01.03.2013) or the chassis CAN (up to 28.02.2013) to the video and radar sensor system control unit.

Parking brake status:

The status of the parking brake is detected/registered by the parking brake indicator switch. The front SAM control unit reads in the status of the parking brake indicator switch directly and sends the status via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

Status of the service brake (ESP® status, standstill coordinator enable): The Electronic Stability Program control unit sends information about the status of the service brake, the ESP® status for release of the standstill coordinator via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

Engine drive torque:

Information about the engine torque currently available is sent by the CDI control unit or ME-SFI [ME] control unit via the via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (from 01.03.2013) to the Electronic Stability Program control unit, which evaluates it accordingly and forwards it via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (from 01.03.2013) to the video and radar sensor system control unit. Acceleration/yaw rate:

The acceleration/turn rate is detected by the yaw rate sensor for lateral and longitudinal acceleration. The sensor for turn rate, lateral and longitudinal acceleration transmits the values for acceleration and yaw rate via the dynamics CAN, Electronic Stability Program control unit and chassis CAN (up to 28.02.2013) or chassis CAN 1 (from 01.03.2013) to the video and radar sensor system control unit.

IMPORTANT On safety and comfort grounds the maximum (positive) acceleration of the automatic distance control is limited to about a = 2.5 m/s2 . It behaves in reverse proportion to the vehicle speed. This means that smaller accelerations are permitted for an increasing vehicle speed.

Driver request via the cruise control lever:

The driver request over the CC lever are directly read in by the steering column tube module control unit. The steering column tube module control unit sends the control signals of the CC lever via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

The driver request "Overtake":

The steering column tube module control unit reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit. Driver request via menu settings in the IC:

The following functions can be selected over the menu settings in the IC:

The instrument cluster transmits the corresponding status for vehicles up to 28.02.2013 via the chassis CAN to the video and radar sensor system control unit. For vehicles from 01.03.2013 the instrument cluster sends the corresponding status via chassis CAN 2, the front SAM control unit and chassis CAN 1 to the video and radar sensor system control unit. Vehicle speed/acceleration, vehicle not in reverse or in a skidding movement:

The vehicle speed is calculated on the basis of the wheel speeds. The acceleration is defined over the increase in RPM and the direction of travel over the wheel rotation direction. The wheel speeds and the wheel rotation directions are recorded by the RPM sensors. The Electronic Stability Program control unit reads in the signals of the RPM sensors directly and sends this via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

GPS signals:

The navigation system of the radio with the Auto-Pilot-System, COMAND controller unit or the radio, in combination with the navigation module adapted via telematics CAN, receives the GPS signals via the multifunction antenna and sends these via interior CAN, front SAM control unit and chassis CAN (up to 28.02.2013) or chassis CAN 1 (from 01.03.2013) to the video and radar sensor system control unit.

Steering wheel angle:

The steering wheel angle is recorded by the steering angle sensor. The steering column tube module control unit reads in the signal from the steering angle sensor directly and sends information via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

Object recognition in the short range:

The short range radar sensor system in the front bumper operates in the 24 GHz frequency range (up to 28.02.2013) or in the 25 GHz frequency range (as of 01.03.2013) for a maximum range of s = 30 m and is integrated into the following assembly parts:

IMPORTANT This is switched off automatically in countries in which the 24 GHz radar sensor system is not approved.

The detection angle of the short range radar sensors is a maximum of ∠ = 130°. A precise angle can be determined within a detection zone of ∠ = 60° and up to ∠ = 130° only after detection of the objects. The DISTRONIC sensors communicate via sensor CAN with the video and radar sensor system control unit.

Object recognition in the long range:

The long range radar is integrated in the DISTRONIC controller unit and operates in the 77 GHz frequency range. With its detection angle of ∠ = 18° the long range radar covers the front area of the vehicle at a length of s = 60 up to 200 m. The range s = 0 m to s = 60 m in front of the vehicle is detected for an angle of ∠ = 60°.

The DISTRONIC controller unit performs a soiling and function test to ensure proper operation after each engine start. The function test requires an object to be located in the detection area of the long range radar which uses this object as a reference value. The DISTRONIC PLUS cannot be activated if a malfunction is established or if there are no objects (reference value) in the detection range of the long range radar sensor. The DISTRONIC PLUS controller unit communicates via the vehicle dynamics CAN with the video and radar sensor system control unit.

Accelerator pedal position:

Operation of the accelerator pedal is registered by the accelerator pedal sensor. The CDI control unit or ME-SFI [ME] control unit reads in the signals from the accelerator pedal sensor directly and sends these via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

Brake pedal position:

Operation of the brake pedal is registered by the brake lights switch. The Electronic Stability Program control unit reads in the status of the brake lights switch directly and sends these via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the video and radar sensor system control unit.

The video and radar sensor system control unit emits the following initial parameters (requests): 

Engage targeted gear, limit gear range:

The video and radar sensor system control unit sends the request "Engage targeted gear" or "Limit gear range" via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the Electronic Stability Program control unit. The Electronic Stability Program control unit evaluates this request as well as further driving dynamics requests internally and transmits them, according to their relevance, via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013), the CDI control unit or the ME-SFI [ME] control unit and drive train CAN to the fully integrated transmission control unit. This request is however to be understood as a recommendation. Downshifting or upshifting of the A/T takes place autonomously itself by the fully integrated transmission control unit, dependent on the current operating condition.

Raise/reduce engine torque:

The video and radar sensor system control unit sends the request "Raise engine torque" or "Lower engine torque" via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the Electronic Stability Program control unit. The Electronic Stability Program control unit evaluates the request as well as further vehicle dynamic requests and sends them according to their relevance from via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the CDI control unit or the ME-SFI [ME] control unit. The CDI control unit or the ME-SFI [ME] control unit implements this request.

Raise/reduce braking torque:

The video and radar sensor system control unit sends the request "Raise braking torque" or "Lower braking torque" via chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013) to the Electronic Stability Program control unit. The Electronic Stability Program control unit directly actuates the traction system hydraulic unit, which reacts by increasing or decreasing the braking torque.

Output acoustic warnings, display system or warning messages: The video and radar sensor system control unit transmits the corresponding requests for vehicles up to 28.02.2013 via the chassis CAN to the IC.

For vehicles from 01.03.2013 the video and radar sensor system control unit sends these requests via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the IC.

The warning tones are emitted by the warning buzzer in the IC. System or warning messages are displayed in the multifunction display of the IC. Switch short range radar system on/off automatically (up to 28.02.2013): The video and radar sensor system control unit switches the short range radar off within protection zones around radio astronomy stations and on again outside of these. The video and radar sensor system control unit transmits the respective request via the sensor CAN to the DISTRONIC (DTR) front bumper sensors.

IMPORTANT The short range radar system can also be switched off and on again manually over the menu "Vehicle settings" in the IC. The IC sends corresponding information for vehicles up to 28.02.2013 via chassis CAN to the video and radar sensor system control unit.

For vehicles from 01.03.2013 the IC sends this request via chassis CAN 2, the front SAM control unit and chassis CAN 1 to the video and radar sensor system control unit. The video and radar sensor system control unit sends the corresponding request via sensor CAN to the DISTRONIC sensors.

IMPORTANT For vehicles as of 01.03.2013 the short range radar sensor system is no longer automatically shutoff. Use of the reduced frequency band range from f = 24.25 GHz to 25.65 GHz means that this is no longer necessary. Both the NATO band and the radio astronomy band are blanked out. Thus operation of the radar sensor system within the protected areas around radio astronomy stations is permissible. The short range radar can also no longer be switched off and on again manually.

The DISTRONIC PLUS includes the following partial functions:

Additional function requirements for DISTRONIC PLUS 

IMPORTANT Model 218

up to model year 2015

with code 233 (DISTRONIC PLUS)

except code 494 (US version)

If the LED SPEEDTRONIC lights up, the DISTRONIC PLUS is deactivated and the function variable SPEEDTRONIC programmed.

The description of the DISTRONIC PLUS function takes place, as an example, in the following chronological sequence:

The sequence can vary depending on the driver requests and the current traffic situation.

Activate DISTRONIC PLUS and drive off automatically 

The DISTRONIC PLUS can only be activated when stationary if there was also a stationary vehicle detected over the radar sensor system. This is displayed by the distance graphic in the multifunction display. If the vehicle starts off, the driver can press the accelerator pedal to confirm the automatic drive off function or alternatively actuate the "Resume from memory" switch on the CC lever. The brake pedal must not be pressed during this time.

The vehicle subsequently starts off automatically, accelerates and follows the vehicle driving immediately ahead at the programmed distance up to the maximum speed to be set.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Automatic distance control 

The automatic distance control can only be activated while driving if a vehicle driving immediately ahead was detected.

If the vehicle driving immediately ahead brakes or accelerates, the DISTRONIC PLUS instigates the following measures for maintain the clearance:

The driver must press on the brake pedal is sees that the instigated measures are not adequate to avoid any possible collision. If the vehicle driving immediately ahead accelerates again, the engine torque is increased and the vehicle also accelerates.

The driver also has the option to accelerate the vehicle (e.g. to overtake a vehicle).

The automatic acceleration is put out of action for as long as the driver uses the accelerator pedal. The multifunction display shows the message "DISTRONIC passive".

If the automatic distance control requires a higher acceleration than the driver prescribes, the driver request is overlaid by the request for automatic distance control.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Change of driving lane (overtaking) 

For overtaking above a speed of v = 60 km/h (45 mph) the vehicle is also accelerated automatically. To do this the driver must initiate the overtaking maneuver by setting the turn signal.

In as far as the automatic distance control is activated, the video and radar sensor system control unit recognizes the intention of the driver to overtake and accelerates the vehicle while taking account of the distance to the vehicle driving immediately ahead. The vehicle then accelerates up to set maximum speed (automatic speed control) after the overtaking maneuver in as far as there was no vehicle driving immediately ahead detected as a target object.

If a vehicle driving immediately ahead is subsequently detected as a target object the automatic speed control function changes over again into the automatic distance control function. The overtaking maneuver is broken off in the following situations:

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Automatic speed control 

If the vehicle is in active distance control and the vehicle driving immediately ahead accelerates above v = 200 km/h (v = 120 mph) or removes itself from the detection area of the radar sensor system, the automatic distance control switches over into the automatic speed control.

IMPORTANT Automatic speed control is described in detail in the separate "Cruise control (CC) Function" subfunction.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Passing through a radio astronomy protection zone 

For vehicles up to 28.02.2013, the short range radar sensor system is automatically switched off in certain protected areas around radio astronomy stations as a result of legal requirements on the 24 GHz radar system (short range radar, band width: f = 5 GHz) in Western Europe. When DISTRONIC PLUS is active, the message "Radar sensor system automatically switched off, see operator's manual" is shown on the multifunction display of the instrument cluster. When the vehicle leaves the protected area, the short range radar sensor system is switched on again automatically. For an activated DISTRONIC PLUS the message "DISTRONIC PLUS available again" is issued.

IMPORTANT For vehicles as of 01.03.2013 the short range radar sensor system is no longer automatically shutoff. Use of the reduced frequency band range from f = 24.25 GHz to 25.65 GHz means that this is no longer necessary. Both the NATO band and the radio astronomy band are blanked out. Thus operation of the radar sensor system within the protected areas of the radio astronomy stations is permissible. It is therefore also no longer necessary to have localization of the vehicle over GPS.

IMPORTANT For vehicles up to 28.02.2013 the driver has the option to switch the short range radar sensor system off and on manually using the "Vehicle settings" menu in the instrument cluster. If one seeks to manually switch on the short range radar sensors within a protected area, the message "Radar sensor system switched off automatically" is displayed in the multifunction display.

Technical implementation (vehicles up to 28.02.2013) 

The protected areas of the radio astronomy stations are stored in the form of Global Positioning System (GPS) coordinates in the video and radar sensor system control unit. The video and radar sensor system control unit evaluates the GPS signals and switches off the short range radar sensor array if necessary.

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Passing over roundabouts, T intersections and freeway exit lane 

The DISTRONIC PLUS function uses map data to adapt the system behavior to the following situations:

This means that if the vehicle driving immediately ahead leaves the detection area of the radar sensor system in one of the above-mentioned traffic situations then the current speed is maintained:

If, after this, no vehicle is detected driving immediately ahead, the vehicle accelerates or decelerates to the established set speed.

IMPORTANT Since traffic situations are subject to alteration, the digital map data has to be regularly updated.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Going back into a lane/person in the front regulation 

If the vehicle driving immediately ahead turns off and there is another vehicle in front, the system only switches over to the new target vehicle if it is moving. The system does not operate for stationary objects unless a preceding vehicle is tracked to a standstill.

If while driving a vehicle turns in front within the safe distance to the vehicle driving immediately ahead, the distance to this new vehicle is regulated.

If the vehicle is in automatic speed control and a vehicle tuns onto the lane driven in this vehicle is registered as the vehicle driving immediately ahead.

If the distance to the moving in vehicle is below the value which was programmed, the DISTRONIC PLUS function brakes the vehicle. If the requested brake power is not adequate the driver must press the brake pedal.

IMPORTANT A negative acceleration (deceleration) over the traction system hydraulic unit is limited to 40% (about a = 4 m/s2 ) of the maximum possible brake power.

DISTRONIC PLUS is thereby deactivated. This process is signaled to the driver by outputting of a signal tone over the warning buzzer and display of a message in the multifunction display.

The driver can subsequently reactivate the DISTRONIC PLUS.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

Automated stopping 

For an active DISTRONIC PLUS the vehicle will follow the vehicle driving immediately ahead to standstill. The service brake is activated if the vehicle is stationary (safety strategy standstill coordinator).

IMPORTANT Securing the vehicle using the DISTRONIC PLUS does not replace securing the vehicle for parking.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

The following traffic situations show the limits of DISTRONIC PLUS.

Obstacles and stationary vehicles:

The DISTRONIC PLUS does not brake for obstacles or stationary vehicles which were not previously registered as the target object.

If, for example, the detected vehicle turns off and there is an obstacle or a stationary vehicle behind it, no automatic intervention by the brake system occurs.

G07300324Courtesy of MERCEDES-BENZ USA

Curves, curved entrances and exits:

The DISTRONIC PLUS can only provides limited detection of vehicles in curves. One's own vehicle can then brake unexpectedly or late.

G07300325Courtesy of MERCEDES-BENZ USA

Vehicles moving across in front of one's own vehicle:

DISTRONIC PLUS may detect vehicles in cross traffic by mistake.

For an activated distance control the vehicle can start off unintended, (e g. at a traffic light with cross-traffic).

G07300326Courtesy of MERCEDES-BENZ USA

Displaced driving style:

DISTRONIC PLUS may not be able to detect vehicles driving displaced to one side. The distance to the vehicle in front becomes too small.

G10050075Courtesy of MERCEDES-BENZ USA

Lane change by other vehicles:

The DISTRONIC PLUS does not yet detect the vehicle moving into the lane. The distance to the vehicle moving into the lane becomes too small.

G10050076Courtesy of MERCEDES-BENZ USA

Narrow vehicles:

The DISTRONIC PLUS does not recognize the vehicle driving immediately ahead on the driving lane because it is too small. The distance to the vehicle in front becomes too small.

G10050077Courtesy of MERCEDES-BENZ USA

Function sequence for PRE-SAFE® brake and BAS PLUS 

The BAS PLUS and the PRE-SAFE® brake assesses the traffic situation in front of the vehicle.

In the following vehicle speed ranges the emergency braking of the driver with the BAS PLUS function is supported or the vehicle is decelerated automatically by the PRE-SAFE® brake function in hazardous situations:

In the case of stationary obstacles the BAS PLUS or the PRE-SAFE® brake is only activated if the vehicle's own vehicle speed is a maximum of v = 72 km/h (v = 45 mph).

If a stationary object is detected in the lane by both the short and long range radar sensor systems (the lane is determined, amongst other things, by the steering wheel angle and vehicle speed, etc.), the BAS PLUS or the PRE-SAFE® brake are activated.

The description of the BAS PLUS and the PRE-SAFE® brake functions is subdivided as follows:

BAS PLUS 

If the driver reacts in a dangerous situation with emergency braking (e.g. output of a collision-critical distance warning) he will be supported by the function BAS PLUS to use the braking distance to the obstacle in an optimal manner.

If there is no actuation of the brake pedal by the driver or the intensity of actuation of the brake pedal by the driver reduces, the brake servo assistance is reduced to the driver braking level and the BAS PLUS function is deactivated. If the driver presses the accelerator pedal, BAS PLUS is also deactivated.

Technical implementation 

The emergency braking is defined over the actuation speed and the actuation strength with which the brake pedal is actuated. To do this, the video and radar sensor system control unit also uses the data from the radar sensor system and also calculates the necessary brake boosting effect while taking account of the distance and the closing speed to the obstacle.

IMPORTANT Parallel to this the function PRE-SAFE® integrated into the Electronic Stability Program control unit evaluates the current requested braking torque and instigates appropriate measures as necessary.

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

PRE-SAFE® brake 

The PRE-SAFE® brake system includes a distance warning function, which warns the driver of any moving or stationary obstacles in his/her lane.

The distance warning takes place in a vehicle speed range of v = 7 to 250 km/h (v = 5 to 150 mph).

In this case differentiation is made between a static distance warning and a collision critical distance warning.

Static distance warning:

The static distance warning is triggered if the time interval between the system vehicle and vehicle driving immediately ahead is less than t = 0.8 s (e.g. in moving traffic). The DISTRONIC warning lamp lights up in the IC.

Collision critical distance warning:

If a moving obstacle in the detection range of the radar sensor system is classified as representing a critical accident situation (a collision within t < 2.6 s), the DISTRONIC warning lamp lights up and the warning buzzer emits an intermittent tone.

The warning output is automatically switched off again when the situation is no longer critical and cannot be acknowledged during an active control.

IMPORTANT The distance warning function can be separately and independently activated by the automatic distance control in the menu "PRE-SAFE® brake" of the instrument cluster.

The distance warning is basically active for an active DISTRONIC PLUS. If the DISTRONIC PLUS is deactivated, actuation of the DISTRONIC warning lamp takes place by the function PRE-SAFE® brake.

Optical warning messages in instrument cluster when a safe distance is not maintained 

G12623136Courtesy of MERCEDES-BENZ USA

If the driver does not react to the warning message, the PRE-SAFE® brake initiates partial braking.

If the driver does not react to the partial braking and if the video and radar sensor system control unit calculates that the collision with the obstacle is unavoidable, the video and radar sensor system control unit instigates emergency braking for t = 1 s and thus reduces the possible consequences of an accident. To do this the video and radar sensor system control unit calculates the required braking torque while taking account of the driving dynamics input factors. The vehicle is braked according to this request.

IMPORTANT Emergency braking is not triggered if the front passenger seat is occupied and the front passenger is not strapped in.

Technical implementation 

To do this the video and radar sensor system control unit receives or transmits the following information or requests:

Input factors:

Initial parameters:

  Electrical function schematic for DISTRONIC PLUS incl. BAS PLUS and PRE-SAFE brake   PE30.30-P-2055-97XAA 
  Overview of system components for driver assistance systems   GF54.00-P-9998FQ
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