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Cruise Control (CC), Function - GF30.30-P-0001FG

Model 213 

up to model year 2021 

G16165745Courtesy of MERCEDES-BENZ USA

Illustration shows model 213 

Function requirements, general 

Cruise control - general 

The cruise control regulates the vehicle speed constantly and automatically to the desired speed set by the driver. To do this, the cruise control evaluates the driver's commands and the current driving condition.

For vehicles with code 239 (DISTRONIC PLUS) the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) the Mercedes-Benz Intelligent Drive control unit, transmits function-relevant requests to the Electronic Stability Program control unit via the suspension FlexRay. The Electronic Stability Program control unit processes these and prioritizes them according to the respective own evaluated parameters.

CC operation 

G16165746Courtesy of MERCEDES-BENZ USA

The cruise control is activated using the resume from memory switch. Here the last stored or momentary vehicle speed is set as the set speed.

The target speed can be altered in steps of v = 1 km/h or v = 10 km/h using the "decelerate and set" switch and the "accelerate and set" switch.

Actuation up to the actuation point increases the set speed by v = 1 km/h. If the switch is pressed beyond the actuation point then the specified speed increases each time by v = 10 km/h. If the switch is held at or beyond the actuation point, the specified speed is changed every t = 0.6 s.

The following input factors are evaluated to implement the function: 

Operating condition for engine/drivetrain: 

The CDI control unit or the ME-SFI [ME] control unit transmits the "Engine running" or "Drivetrain operational" signal via the drive CAN, powertrain control unit and suspension FlexRay to the Electronic Stability Program control unit, and for vehicles with code 239 (DISTRONIC PLUS) also to the Distance Pilot DISTRONIC controller unit, or in vehicles with code 23P (Driver Assistance Package) to the Mercedes-Benz Intelligent Drive control unit.

IMPORTANT The CDI control unit or the ME-SFI [ME] control unit, amongst other things, coordinates acceleration, deceleration or switching requirements. In doing so it prioritizes requests according to their relevance, while taking account of the additional variables such as the charge level of the high voltage on-board electrical system, the operating condition of the ancillaries or requests from the comfort systems such as the AAC.

Engaged gear range (transmission 725): 

Information about the engaged drive range is transmitted by the fully integrated transmission control unit via the drive CAN, powertrain control unit and suspension FlexRay to the Electronic Stability Program control unit, and for vehicles with code 239 (DISTRONIC PLUS) also to the Distance Pilot DISTRONIC controller unit, or in vehicles with code 23P (Driver Assistance Package) to the Mercedes-Benz Intelligent Drive control unit.

Vehicle speed: 

The vehicle speed is calculated by the Electronic Stability Program control unit from the wheel speeds.

For vehicles with code 239 (DISTRONIC PLUS), the Electronic Stability Program control unit also transmits the wheel speed signals via chassis FlexRay to the DISTRONIC Distance-Pilot controller unit.

For vehicles with code 23P (Driving Assistance Package), the Electronic Stability Program control unit additionally transmits the wheel speed signals to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.

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 transmits the operation signals from the CC lever via the suspension FlexRay to the Electronic Stability Program control unit, and for vehicles with code 239 (DISTRONIC PLUS) also to the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive control unit.

Accelerator pedal position: 

The powertrain control unit transmits information about the accelerator pedal position via the suspension FlexRay to the Electronic Stability Program control unit, and for vehicles with code 239 (DISTRONIC PLUS) also to the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive control unit.

The following initial parameters (requests) are issued to implement the function: 

Increase/reduce the drive torque: 

For vehicles except code 239 (DISTRONIC PLUS) and except code 23P (Driving Assistance Package), the Electronic Stability Program control unit evaluates the input factors and other driving dynamic requests and transmits the "Increase/reduce drive torque" request via the suspension FlexRay, powertrain control unit and engine CAN to the CDI control unit or the ME-SFI [ME] control unit.

For vehicles with code 239 (DISTRONIC PLUS) the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) the Mercedes-Benz Intelligent Drive control unit transmits the "Increase/reduce drive torque" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this and transmits it according to its priority via the chassis FlexRay, powertrain control unit and engine CAN 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.

Engage target gear (downshift or upshift) (transmission 725): 

For vehicles except code 239 (DISTRONIC PLUS) and except code 23P (Driving Assistance Package), the Electronic Stability Program control unit evaluates the input factors and other driving dynamic requests and transmits the "Engage requested gear" request via the suspension FlexRay, powertrain control unit and drive CAN to the fully integrated transmission control unit.

For vehicles with code 239 (DISTRONIC PLUS) the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) the Mercedes-Benz Intelligent Drive control unit transmits the "Engage requested gear" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this and transmits it according to its priority via the chassis FlexRay, powertrain control unit and drivetrain CAN to the fully integrated transmission control unit.

This request is to be understood as a shift recommendation.

Downshifting or upshifting of the automatic transmission takes place autonomously by the fully integrated transmission control unit dependent on the current operating condition.

Raise/reduce braking torque: 

Fir vehicles except code 239 (DISTRONIC PLUS) and except code 23P (Driving Assistance Package), the Electronic Stability Program control unit evaluates the input factors and actuates the traction system hydraulic unit accordingly.

For vehicles with code 239 (DISTRONIC PLUS) the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) the Mercedes-Benz Intelligent Drive control unit transmits the "Increase/reduce braking torque" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit evaluates these and actuates the traction system hydraulic unit appropriately.

The traction system hydraulic unit reacts by increasing or reducing the braking torque.

IMPORTANT

Model 213.016/050/053/153/216

up to model year 2021

For model the kinetic energy is converted within defined limits into electrical energy (regenerative braking). If the required braking torque exceeds the deceleration through regenerative braking, the regenerative braking system control unit also actuates Electronic Stability Program control unit and the traction system hydraulic unit and therefore the service brake.

Cruise control encompasses the following subfunctions:

Additional automatic speed control function requirements 

Function sequence for automatic speed control 

Through actuation of the "Resume from memory" switch the last set speed stored is applied, provided a set speed was stored since the last engine start. If no set speed was stored, the current vehicle speed is set as the set speed. The target speed is displayed in the IC.

For vehicles except code 239 (DISTRONIC PLUS) and except code 23P (Driving Assistance Package), the Electronic Stability Program control unit transmits the set speed (specified speed) via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.

For vehicles with code 239 (DISTRONIC PLUS) the Distance Pilot DISTRONIC controller unit, or for vehicles with code 23P (Driving Assistance Package) the Mercedes-Benz Intelligent Drive control unit transmits the set speed (specified speed) via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.

IMPORTANT The driver also has the option to accelerate beyond the set target speed through actuation of the accelerator pedal (for example when overtaking). The set speed is regulated again after removal of the acceleration request (releasing the accelerator pedal).

The following events deactivate the automatic speed control:

The following activities are started in order to reach or maintain the set speed:

Function sequence, variable speed limiter 

The DTCO has the following subfunctions:

Additional function sequence for variable speed limiter (except code 494 (USA version)) 

IMPORTANT If switching takes place on the variable SPEEDTRONIC on the CC lever, the automatic speed control is deactivated.

Function sequence for variable speed limiter (except code 494 (USA version)) 

The variable speed limiter can be used to limit the vehicle's maximum speed to a freely selectable value (e.g. v = 50 km/h in urban traffic). The driver can accelerate the vehicle up to the set limit.

The following events deactivate the variable speed limiter:

Function sequence for permanent limiter 

The maximum speed of the vehicle can be limited in steps of v = 10 km/h from v = 160 to 240 km/h. Adjustment of the permissible maximum speed takes place in the menu "Settings", "Vehicle" and "Limitation (winter tires)" in the head unit. For navigation in the operating menu the following options are available:

For vehicles except code 239 (DISTRONIC PLUS) and except code 23P (Driving Assistance Package), the head unit transmits the set maximum speed via the user interface CAN, electronic ignition lock control unit and suspension FlexRay to the Electronic Stability Program control unit.

For vehicles with code 239 (DISTRONIC PLUS), the head unit transmits the set maximum speed via user interface CAN, electronic ignition lock control unit and chassis FlexRay to the DISTRONIC Distance-Pilot controller unit.

For vehicles with code 23P (Driving Assistance Package), the head unit sends the set maximum speed via the user interface CAN, electronic ignition lock control unit, and the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.

Approximately v = 10 km/h before reaching the set maximum speed a message appears in the instrument cluster multifunction display that indicates a maximum speed limitation. The driver can accelerate the vehicle up to the set maximum speed. The head unit transmits the set maximum speed via the user interface CAN to the IC.

If the maximum speed was reached the following activities are started:

IMPORTANT The permanent limiter also remains active for a switched off variable speed limiter.

  Electrical function schematic for cruise control (CC) Model 213 up to model year 2021 except code 239 (Adaptive cruise control Pro (DISTRONIC PRO)) except code 23P (Drive package) PE30.30-P-2051-97DBA 
    Model 213 up to model year 2021 with code 239 (Adaptive cruise control Pro (DISTRONIC PRO)) Model 213 up to model year 2021 with code 23P (Drive package) PE30.30-P-2051-97DBB 
  Overview of system components for driver assistance systems   GF54.00-P-9998FG