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Cruise Control (CC), Function - GF30.30-S-0001TRA

Model 447 

With Code ET4 (Active Distance Assist DISTRONIC) 

except code MS1 (Cruise control) 

except code XM0 (Facelift) 

Model 447 

With Code MS1 (Cruise control) 

except code ET4 (Active Distance Assist DISTRONIC) 

except code XM0 (Facelift) 

Model 448 

With Code ET4 (Active Distance Assist DISTRONIC) 

except code MS1 (Cruise control) 

Model 448 

With Code MS1 (Cruise control) 

except code ET4 (Active Distance Assist DISTRONIC) 

G16501008Courtesy of MERCEDES-BENZ USA

Shown: model 447.8 (with engine 651) 

Shown: model 447.6/7 (with engine 622, 651) 

G16501009Courtesy of MERCEDES-BENZ USA

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 ET4 (DISTRONIC PLUS) the DISTRONIC control unit (DTR) sends function-relevant requests via the chassis CAN to the Electronic Stability Program control unit (ESP). The Electronic Stability Program (ESP) control unit processes these and prioritizes them according to the respective own evaluated parameters.

Operation of cruise control using the cruise control lever, Shown On Model 447.8 

G16501010Courtesy 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.

Using the switches "decelerate" and "set" and the switches "accelerate" and "set", the target speed can be altered in steps of v = 1 km/h or v = 10 km/h.

Actuation up to the actuation point increases the set speed by v = 1 km/h. If the respective switch is actuated beyond the pressure point, the specified speed changes by v = 10 km/h in each case. If the respective switch is held at or beyond the pressure point, the specified speed is changed every t = 0.6 s.

The following input factors are evaluated to implement the function:

Operating condition of engine/drivetrain (function requirements). 

The CDI control unit or ME-SFI [ME] control unit (N3/34) transmits the signal "Engine running" or "Drivetrain operational" via the chassis CAN to the Electronic Stability Program control unit (ESP) and, for vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8), also to the DISTRONIC (DTR) control unit.

IMPORTANT All acceleration, deceleration or switching requests are coordinated by the CDI control unit or the ME-SFI [ME] control unit. The CDI control unit prioritizes requests according to their relevance, while taking account of the additional variables such as the operating condition of the ancillaries or requests from the comfort systems such as the AAC.

Engaged gear range (for transmission 722.9) (function requirements). 

The fully integrated transmission control (VGS) electric controller unit sends information regarding the engaged gear range via the drive train CAN, CDI control unit or ME-MFI [ME] control unit and chassis CAN to the Electronic Stability Program control unit (ESP) and, for vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8), also via the drive train CAN, CDI control unit or ME-MFI [ME] control unit and chassis CAN to the DISTRONIC (DTR) control unit.

Vehicle speed  :

The vehicle speed is calculated by the Electronic Stability Program (ESP) control unit based on the wheel speed.

For vehicles with code ET4 (DISTRONIC PLUS) (model 447.8) the Electronic Stability Program control unit (ESP) sends the vehicle speed via the chassis CAN to the DISTRONIC control unit (DTR).

Driver request via the cruise control lever  :

The driver requests made over the CC lever are read in directly by the steering column tube module (MRM) control unit. The steering column tube (MRM) module control unit transmits the control signals from the cruise control lever via the chassis CAN to the Electronic Stability Program control unit (ESP) and, for vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8), also to the DISTRONIC (DTR) control unit.

The CDI control unit or ME-MFI [ME] control unit transmits information about the accelerator pedal position via the chassis CAN to the Electronic Stability Program control unit (ESP) and, for vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8), also to the DISTRONIC (DTR) control unit.

Accelerator pedal position  :

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

Increase/reduce the drive torque  :

For vehicles without code ET4 (DISTRONIC PLUS) the Electronic Stability Program control unit (ESP) evaluates the input factors as well as further driving dynamics request and transmits the request "increase/reduce drive torque" via the chassis CAN to the CDI control unit or the or ME-SFI [ME] control unit.

For vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8) the DISTRONIC control unit (DTR) transmits the request "increase/reduce drive torque" via chassis CAN to the Electronic Stability Program control unit (ESP). The Electronic Stability Program control unit (ESP) processes this and transmits it according to its priority via the chassis CAN to the CDI control unit or ME-SFI [ME] control unit.

The CDI control unit or the ME-SFI [ME] control unit implements this request.

Engage targeted gear (back or upshift) (for transmission 722.9) 

For vehicles without code ET4 (DISTRONIC PLUS) the Electronic Stability Program control unit (ESP) evaluates the input factors as well as further driving dynamics request and transmits the request "Engage targeted gear" via the chassis CAN, CDI control unit or ME-SFI [ME] control unit and drive train CAN to the fully integrated transmission electric controller unit (VGS).

For vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8) the Electronic Stability Program control unit (ESP) sends the request "Engage targeted gear" via the chassis CAN to the Electronic Stability Program control unit (ESP). The Electronic Stability Program (ESP) control unit processes this and transmits it according to its priority via the chassis CAN, CDI control unit or ME-SFI [ME] control unit and drive train CAN to the fully integrated transmission electric controller unit (VGS).

This request is to be understood as a shift recommendation.

Downshifting or upshifting of the A/T takes place autonomously by the fully integrated transmission electric controller unit (VGS), dependent on the current operating condition.

Raise/reduce braking torque  :

For vehicles without code ET4 (DISTRONIC PLUS) the Electronic Stability Program control unit (ESP) evaluates the input factors and actuates the traction system hydraulic unit appropriately.

For vehicles with code ET4 (DISTRONIC PLUS) (model 447.8 or model 448.8) the DISTRONIC control unit (DTR) transmits the request "increase/reduce braking torque" via chassis CAN to the Electronic Stability Program control unit (ESP).

The Electronic Stability Program (ESP) 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.

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 set speed is shown in the IC (IC) control unit's multifunction display.

Model 447.8, model 448.8 

For vehicles without code ET4 (DISTRONIC PLUS) the Electronic Stability Program control unit (ESP) sends the set speed (target speed) via the chassis CAN, Gateway for the user interface CAN and user interface CAN to the IC control unit (IC).

For vehicles with code ET4 (DISTRONIC PLUS) the DISTRONIC control unit (DTR) sends the set speed (target speed) via the chassis CAN, Gateway for the user interface CAN and user interface CAN to the IC control unit (IC).

MODEL 447.6/7, MODEL 448.7 

The Electronic Stability Program control unit (ESP) sends the vehicle speed via chassis CAN to the IC control unit (IC).

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 for SPEEDTRONIC 

The SPEEDTRONIC comprises the following subfunctions:

Additional function requirements for variable SPEEDTRONIC 

IMPORTANT The steering column tube module control unit (MRM) actuates the LED SPEEDTRONIC directly.

Function sequence for variable SPEEDTRONIC 

The variable SPEEDTRONIC 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.

If the set limit was reached, the following activities are started:

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

The following events deactivate the variable SPEEDTRONIC:

Function sequence for permanent limiter 

The maximum speed of the vehicle can be limited in steps of v = 10 km/h from v = 160 km/h to 240 km/h. Adjustment of the maximum speed takes place in the menu "Settings", "Vehicle" and "Limitation (winter tires)" the IC control unit (IC).

Model 447.8 or model 448.8 

For vehicles without code ET4 (DISTRONIC PLUS) the IC control unit (IC) sends the set maximum speed (target speed) via the chassis CAN, Gateway for the user interface CAN and chassis CAN to the Electronic Stability Program control unit (ESP).

For vehicles with code ET4 (DISTRONIC PLUS) the IC control unit (IC) sends the set maximum speed via the user interface CAN, Gateway for the user interface CAN and chassis CAN to DISTRONIC control unit (DTR).

Model 447.6/7 or model 448.7 

The IC control unit (IC) sends the set maximum speed via chassis CAN to the Electronic Stability Program control unit (ESP).

Approximately v = 10 km/h before reaching the set maximum speed a message appears in the IC control unit (IC) multifunction display that indicates a maximum speed limitation. The driver can accelerate the vehicle up to the set maximum speed.

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

  Electrical function schematic for cruise control (CC) Model 448.8 with code MS1 (Cruise control) except code ET4 (Active Distance Assist DISTRONIC) PE30.30-S-2051-97VDA
    Model 448.8 with code ET4 (Active Distance Assist DISTRONIC) except code MS1 (Cruise control) PE30.30-S-2051-97VDB
    Model 448.7 with code MS1 (Cruise control) except code ET4 (Active Distance Assist DISTRONIC) PE30.30-S-2051-97VDC
    Model 447.8 with code MS1 (Cruise control) except code ET4 (Active Distance Assist DISTRONIC) except code XM0 (Facelift) PE30.30-S-2051-97TRA
    Model 447.8 with code ET4 (Active Distance Assist DISTRONIC) with code MS1 (cruise control) except code XM0 (Facelift) PE30.30-S-2051-97TRB
    Model 447.6/7 with code MS1 (Cruise control) except code ET4 (Active Distance Assist DISTRONIC) except code XM0 (Facelift) PE30.30-S-2051-97TRC 
  Overview of system components for driver assistance systems   GF54.00-S-9998TRA
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