Component Description For Fully Integrated Transmission Control Unit - GF27.60-P-5165RFH
Transmission 724.2 in model 205, 253
View of fully integrated transmission control controller unit (Y3/8) from top left
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.
Task
The fully integrated transmission control unit determines the current operating condition of the vehicle and controls all function sequences of the hydraulic transmission control. This includes all gear change sequences, the engaging of gear ranges "P", "R", "N" and "D", and the control of the electric auxiliary oil pump (M42).
The software of the transmission control in the fully integrated transmission control unit is flashable, i.e. it can be replaced (updated). The fully integrated transmission control unit implements these tasks as follows:
- Reading in of sensors and signals
- Evaluation of input factors
- Actuation of components
- Sending signals
Reading in of sensors and signals
These input factors are read in via the following connections:
- Direct line
- Drive train CAN (CAN C1)
Direct line
The fully integrated transmission control unit reads in the signals from the following components via direct lines:
- Wet clutch oil pressure sensor (Y3/8b1)
- D/R oil pressure switch 1 and 2 (Y3/8b3, Y3/8b4) (redundant design)
- 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)
Drive train CAN
The fully integrated transmission control unit reads in the following signals via the drive train CAN, among other things:
- From the CDI control unit (N3/9) (diesel engine) or the ME-SFI [ME] control unit (N3/10) (gasoline engine):
- Engine running
- Engine speed
- Engine torque
- Accelerator pedal position
- Wet clutch request
- From the powertrain control unit (N127):
- Terminal 15 status
- Wheel speeds
- Service brake, status
Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.
Actuation of components
The fully integrated transmission control unit actuates the following components via direct lines:
- Electric auxiliary oil pump
- Park pawl lift solenoid (Y3/8l1)
- Working pressure control solenoid valve (Y3/8y1)
- K1 clutch control solenoid valve (Y3/8y2)
- K2 clutch control solenoid valve (Y3/8y3)
- K3 clutch control solenoid valve (Y3/8y4)
- B1 multidisk brake control solenoid valve (Y3/8y5)
- B2 multidisk brake control solenoid valve (Y3/8y6)
- B3 multidisk brake control solenoid valve (Y3/8y7)
- Wet clutch control solenoid valve (Y3/8y9)
- D/R switchover valve (Y3/8y10)
- Park pawl switchover valve (Y3/8y11)
Sending signals
The fully integrated transmission control unit transmits the following signals via the drive train CAN, among other things:
- Driving stage engaged
- Active transmission mode
- Selector lever position
- Engine torque request
- Engine speed request
- Status of transmission control
- Limp-home mode status
- Display messages request
- Diagnostic data
The powertrain control unit, the electronic ignition lock control unit (N73) and the head unit (A26/17) form interfaces (Gateways) for data exchange with control units that are not connected to the drive train CAN.
| Wiring diagram for fully integrated transmission control unit | PE27.19-P-2103-97FBA |