Component description for fully integrated transmission control unit - GF27.60-P-5165AHO

TRANSMISSION 724.2 in MODEL 212 

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

Location 

The fully integrated transmission control unit and the electric transmission oil pump (M42) are integrated into the fully integrated transmission control controller unit, which is located on the underside of the transmission housing in the oil pan.

The electrohydraulic parking interlock control (Parking module) is connected by bolted connections level with the fully integrated transmission control controller unit to the transmission housing.

Task 

General 

The fully integrated transmission control unit with its own independent diagnostic system determines the current operating condition of the vehicle and actuates all the gear change sequences, taking shift comfort and the driving situation into consideration, as well as the engagement of gear ranges "P", "R", "N", "D" and the operating time or rotational speed of the electrical transmission oil pump.

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 to program the control units is stored on the Xentry diagnostics update DVD.

CAN data bus 

The fully integrated transmission control unit is connected via the drive train CAN (CAN C) to the vehicle's CAN network, and exchanges data with other control units.

For vehicles up to facelift 13 

• Circuit 50 signal, influence on fault storage

Regenerative braking system control unit (N30/6) 

• 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, 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) request for shifting to "N", power flow interruption
• Brake lights switch (S9/1), change of shift strategy, brake vehicle, transmission shifts down earlier
• ESP specified torque, torque reduction or torque increase

Steering column tube module control unit (N80) 

• Steering wheel downshift button (S110/1)
• Steering wheel upshift button (S111/1)

Front SAM control unit with fuse and relay module 

• Diagnosis request

Trailer recognition control unit (N28/1) (with code (550) Trailer hitch) 

• Trailer recognition signal

CDI control unit or ME-SFI control unit 

Requests for catalytic converter heating

Switching request

• Engine torque
• Engine coolant temperature

The CDI control unit (N3/9) or the ME-SFI [ME] control unit (N3/10) acts as an interface between the drive train CAN and the chassis CAN (CAN E).

As of facelift 13 the current chassis CAN will be replaced by the chassis CAN 1 (CAN E1). An additional chassis CAN 2 (CAN E2) is used between the instrument cluster (A1) and the front SAM control unit with fuse and relay module (N10/1). The ME-SFI [ME] control unit or the CDI control unit forms the interface between the drive train CAN and the chassis CAN 1. The interface between chassis CAN 1 and chassis CAN 2 is formed by the front SAM control unit with fuse and relay module.

• Engine speed
• Engine load
• Kick-down
• engine speed limitation active
• limp-home mode engine control
• Electrical machine actual torque (A79/1)
• Electrical machine specified torque
• Wet clutch specified creep torque

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 

• Circuit 31
• Circuit 87
• Wet clutch oil pressure sensor (Y3/8b1)
• Oil pressure switch D/R 1 and D/R 2 (Y3/8b3, Y3/8b4) (redundant version)
• Turbine wheel rpm sensor (Y3/8n1)
• Internal transmission 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)

Direct output signals 

• Electric transmission oil pump (M42)
• Park pawl lift solenoid (Y3/8l1)
• Working pressure control solenoid valve (Y3/8y1)
• Clutch control solenoid valve K1 (Y3/8y2)
• Clutch control solenoid valve K2 (Y3/8y3)
• Clutch control solenoid valve K3 (Y3/8y4)
• Multidisk brake control solenoid valve B1 (Y3/8y5)
• Multidisk brake control solenoid valve B2 (Y3/8y6)
• Multidisk brake control solenoid valve B3 (Y3/8y7)
• Wet clutch control solenoid valve (Y3/8y9)
• D/R switchover valve (Y3/8y10)
• Park pawl switchover valve (Y3/8y11)

The following listing, for example, represents the Important CAN messages which are exchanged over the CAN network.

CAN input signals 

Electronic ignition lock control unit (N73) 

• Enable from drive authorization system stage 3 (DAS 3)

CAN output signals 

Instrument cluster 

• Transmission mode selection for transmission mode display (A1p16)
• Selector lever position and status of button "P" for gear indicator (A1p12)
• Actuation of indicator lamp for engine diagnosis (A1e58)

Regenerative braking system control unit 

• Wheel torque factor, overall gear ratio
• Actual gear, target gear
• Transmission variant, recognition of basic variants, difference in gear ratios

Front SAM control unit with fuse and relay module 

• Diagnostic data

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" or "N"
• Specified engine idle rpm (for wet clutch actuation)
• Wet clutch actual torque
• Wet clutch status
• Emergency operation transmission control
• Electric transmission oil pump status
• Transmission oil temperature (for actuation of transmission cooling coolant circulation pump (M13/7))

Wiring diagram for fully integrated transmission control unit

PE27.19-P-2103-97DAB