Electric differential lock (EAGGS), function

P35.40-2073-79

The following table provides a model and major assembly installation overview:

Function requirements for electric differential lock (EAGGS), general

 Wheel speed signal present

 Drivetrain operational signal

 On-board electrical system voltage

 Ignition terminal status

 To check that the function requirements are met, the electronic differential control unit reads in the following signals via the AMG CAN and the AMG suspension control unit:

 Wheel speed signal via user interface CAN, electronic ignition lock control unit, chassis FlexRay and Electronic Stability Program control unit.

 Drivetrain operational signal via drive train CAN and ME-SFI control unit.

 On-board electrical system voltage and ignition terminal status via user interface CAN and electronic ignition lock control unit.

Electric differential lock, general

The electric differential lock is integrated in the rear axle differential. It improves traction and also increases driving stability when accelerating from stationary, while cornering or when changing lanes quickly. This guarantees greater responsiveness and more accurate handling. A multidisk clutch operated via actuation of the differential lock actuator is used to reduce the differences in speed or wheel slip. As a result, the locking effect can always be adapted to suit the current driving situation.

 WIS Service Media
wsm://03_ 201500_01

P35.40-2071-76

Function sequence of electric differential lock

The electronic differential control unit actuates the differential lock actuator, which closes the differential lock via the sprocket (3), adjustment ring (2), balls (1), ramp disk (4), needle roller bearing (5), thrust ring (6), thrust pieces (7), pressure plate (8) and multidisk clutch (9). The differential lock actuator Hall sensor integrated in the differential lock actuator reports the position and the differential lock actuator temperature sensor also integrated reports the temperature of the differential lock actuator back to the Electronic Stability Program control unit via the AMG CAN, AMG chassis control unit, and vehicle dynamics CAN. Over the same path the electronic differential control unit transmits the locking ratio of the electronic differential lock and the status of the differential lock actuator back to the Electronic Stability Program control unit.

 WIS Service Media
wsm://03_ 201500_02

Reading of signals and actuation of components

The following signals are processed by the electronic differential control unit:

Supplemental Restraint System control unit (N2/10)

 Yaw rate

 Vehicle acceleration

Electronic Stability Program control unit

 ESP® display mode

 Transmission mode selection individual mode status

 Brake system status

 Electric differential lock locking ratio request

ME-SFI [ME] control unit

 Engine running status

 Drivetrain status

Fully integrated transmission control control unit

 Transmission oil temperature

The following components are actuated by the electronic differential control unit:

 Differential lock actuator

 Multifunction display

 Diagnostic connector

The supplemental restraint system control unit sends the "yaw rate" and "vehicle acceleration" signals via the vehicle dynamics CAN to the Electronic Stability Program and via the vehicle dynamics CAN, AMG chassis control unit, and AMG CAN to the electronic differential control unit. After receiving the above signals, the Electronic Stability Program control unit transmits the request for the locking ratio of the differential lock via the vehicle dynamics CAN, the AMG suspension control unit and the AMG CAN to the electronic differential control unit.

The Electronic Stability Program control unit transmits the signals for the ESP® display mode, the transmission mode selection individual mode status and the brake system status via the chassis FlexRay, the electronic ignition lock control unit and the user interface CAN, the AMG suspension control unit and the AMG CAN to the electronic differential control unit.

The ME-SFI control unit transmits the signals for the engine running status and the drive train status via the drive train CAN, the AMG suspension control unit and the AMG CAN to the electronic differential control unit.

The fully integrated transmission control unit transmits the transmission oil temperature via the drive train CAN, the AMG suspension control unit and the AMG CAN to the electronic differential control unit.

The DYNAMIC SELECT switch allows the driver to choose between one "Individual" and various preconfigured transmission modes. The driver chooses the required transmission mode by operating the DYNAMIC SELECT switch and receives operation feedback in the instrument cluster and the head unit. The status of the DYNAMIC SELECT switch is read in by the left lower control panel. The left lower control panel transmits the signal via the LCP LIN, the Audio/COMAND control panel, the telematics CAN, the head unit, the user interface CAN, the electronic ignition lock control unit and the chassis FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit puts the information for the chosen transmission mode on the chassis FlexRay. The control units relevant for the new transmission mode receive the information and switch to the stored parameters for the particular transmission mode.

In the event of temporary or permanent system failures, a fault message is output in the multifunction display. The signal for the display message is sent by the AMG suspension control unit, the user interface CAN and the instrument cluster to the multifunction display.

Diagnostic communications of the differential lock actuator take place via the electronic differential control unit, the AMG CAN, the AMG suspension control unit, the user interface CAN, the electronic ignition lock control unit, the diagnostic CAN and the diagnostic connector.