(Component Description For Fully Integrated Transmission Control Unit - GF27.60-P-5165FH)
Transmission 725 in model 238
up to model year 2021
View of fully integrated transmission control controller unit (Y3/8) from above
Location
The fully integrated transmission control unit is integrated in the fully integrated transmission control controller unit, which is located in the oil pan at the bottom of the transmission housing.
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 control unit for the fully integrated transmission control (VGS) is flashable i.e. the complete software in the control unit can be changed (replaced). The software required for control unit programming is stored on the diagnosis software DVD.
CAN bus
The fully integrated transmission control unit is connected via the drive train CAN (CAN C1) to the vehicle's CAN network and exchanges data with other control units.
Reading in of signals
The fully integrated transmission control unit reads in input signals via following connections:
- Direct line
- Drive train CAN
Direct line
The fully integrated transmission control unit reads in the signals from the following components via direct lines:
- Emergency-P from electronic ignition lock control unit (N73)
- Turbine wheel rpm sensor (Y3/8n1)
- Input speed rpm sensor (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)
Drive train CAN
The fully integrated transmission control unit also reads in the following signals via drive train CAN:
- Vehicle speed
- Circuit 15 status
- Release of drive authorization system stage 4 (FBS4)
- "Key-P function" request
- Circuit 50 signal, influencing fault storage
- Wheel speed and direction of rotation, substitute value 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
- Brake light switch status (S9/1), change of shift strategy, brake vehicle, automatic transmission downshifts earlier
- ESP® specified torque, torque reduction or torque increase
- Steering wheel downshift button signal (S110/1)
- Steering wheel upshift button signal (S111/1)
- DIRECT SELECT lever signal (S1613)
- Requests for catalytic converter heating
- Shift request
- Selector lever position signal
- Transmission mode selection signal
- Engine torque
- Engine coolant temperature
- Engine speed
- Kickdown status
- Rpm limitation active status
- Status of engine management
- Engine running status
- Trailer recognition signal
Evaluation of input factors
The read-in input factors are evaluated by the fully integrated transmission control unit.
Actuation of components
The actuation of the components takes place via the following connections:
- Direct line
- Drive train CAN
Direct line
The fully integrated transmission control unit actuates the following components via direct lines:
- 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)
Drive train CAN
The fully integrated transmission control unit transmits the following information via the drive train CAN:
- Selector lever position
- Transmission mode selection
- Drive position
- 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
- Wheel torque factor, overall gear ratio
- Transmission variant, recognition of basic variants, difference in gear ratios
| Wiring diagram for fully integrated transmission control unit | PE27.19-Q-2103-97DCA |