Component Description For Fully Integrated Transmission Control Unit - GF27.60-P-5165ANG

Transmission 725.0 (except 725.017) in model 205 

View of fully integrated transmission control controller unit (Y3/8) from above 

Courtesy of MERCEDES-BENZ USA

Location 

The fully integrated transmission control unit is integrated in the fully integrated transmission controller unit which is located in the bottom of the automatic transmission.

Tasks 

The fully integrated transmission control unit determines the current operating condition of the vehicle and actuates all gear change sequences taking shifting comfort and the driving situation into consideration.

Flash programming 

The transmission control system in the fully integrated transmission control unit (VGS) is flashable i.e. the software in the control unit can be changed (replaced). The software required for control unit programming is stored on the diagnosis software DVD.

The fully integrated transmission control unit is connected over the drive CAN (CAN C1) to the vehicle network and exchanges data with other control units.

Input and output signals 

The following input signals are evaluated by the fully integrated transmission control unit and the appropriate output signals are generated:

• Direct input signals 
• Direct output signals 
• CAN input signals 
• CAN output signals 

Direct input signals 

• Emergency-P from electronic ignition lock control unit (N73)
• Turbine wheel RPM sensor (Y3/8n1)
• RPM sensor for internal input speed (Y3/8n2)
• Output shaft RPM sensor (Y3/8n3)
• Transmission oil temperature sensor (Y3/8s2) (integrated into fully integrated transmission control unit)
• Park pawl position sensor (Y3/8s4)
• Pressure sensor (Y3/8b5)

Direct output signals 

• Electric auxiliary oil pump (M42)
• Park pawl lift solenoid (Y3/8l1)
• Lubrication pressure solenoid (Y3/8y12)
• K81 clutch control solenoid (Y3/8y13)
• K38 clutch control solenoid (Y3/8y14)
• K27 clutch control solenoid (Y3/8y15)
• B08 multidisk brake control solenoid (Y3/8y16)
• B05 multidisk brake control solenoid (Y3/8y17)
• B06 multidisk brake control solenoid (Y3/8y18)
• Working pressure solenoid (Y3/8y19)
• Torque converter lockup clutch solenoid (Y3/8y20)

CAN input signals 

• Instrument cluster (A1)
  • Vehicle speed
• Electronic ignition switch control unit
  • Terminal status of terminal 15
  • Release of drive authorization system stage 4 (FBS4)
  • "Key-P function" request
  • Status of circuit 50, influence on fault storage
• Electronic Stability Program control unit (N30/4)
  • Wheel speeds and direction of rotation, substitute values in the event of failure of the output shaft RPM sensor
  • Adjusted braking torque, change of shift strategy, brake the vehicle, automatic transmission shifts down earlier.
  • Vehicle lateral acceleration at center of gravity, adaptation of shift strategy, detection of dynamic driving style
  • Cruise control operation, special shifting strategy
  • Electronic Stability Program (ESP®) requested shift into "N", interruption of power flow
  • Braking torque status, change of shift strategy, brake vehicle, automatic transmission shifts down earlier.
  • ESP® specified torque, torque reduction or torque increase
  • Transmission mode selection
• Steering column tube module control unit (N80)
  • Steering wheel downshift button status (S110/1)
  • Steering wheel upshift button status (S111/1)
  • Shift position of DIRECT SELECT lever (S16/13)
• CDI control unit (N3/9) (diesel engine) or ME-SFI [ME] control unit (N3/10) (gasoline engine)
  • Requests for catalytic converter heating
  • Shift request
  • Engine torque
  • Engine coolant temperature
  • Engine speed
  • Engine load
  • Kickdown
  • RPM limitation ACTIVE
  • Engine management limp-home mode
  • Status of engine management
  • Engine running status
• Trailer recognition control unit (N28/1) (with CODE 550 (Trailer hitch))
  • Trailer recognition signal
• Audio/COMAND control panel (A40/9)
  • Status of DYNAMIC SELECT switch (N72/4s11)
• Left front door control unit (N69/1) (with code 889 (KEYLESS-GO))
  • Status of left front door

CAN output signals 

• Instrument cluster
  • Selector lever position for gear indicator
  • Program selection for drive program display
  • Message display
• CDI control unit or ME-SFI control unit
  • Drive position
  • Transmission mode
  • Actual gear, target gear
  • Engine torque reduction request
  • Starter enable in selector lever position "P", "N"
  • Target engine speed in neutral (for actuation of torque converter lockup clutch)
  • Status of torque converter lockup clutch
  • Transmission limp-home mode
• Electronic Stability Program control unit
  • Wheel torque factor, overall gear ratio
  • Actual gear, target gear
  • Transmission variant, recognition of basic variants, difference in gear ratios