GF27.19-P-4020AHT Component Description For Intelligent Servo Module For Direct Select
GF27.19-P-4020AHT Component Description For Intelligent Servo Module For DIRECT SELECT
- TRANSMISSION 722.931 in MODEL 221.074 /174, 216.374
Automatic transmission viewed from left
A80 Intelligent servo module for DIRECT SELECT
Location
The intelligent servo module for DIRECT SELECT is mounted on the left of the transmission housing.
Task
General
The driver's gear range request "P", "R", "N", "D" is not transmitted from the control to the transmission via a rod (mechanical connection) but by means of an electronic connection ("wire"). This electronic connection consists of the DIRECT SELECT gear selector switch (S16/13) and the intelligent servo module for DIRECT SELECT. The overall system is called "Shift-by-wire".
Basic functions
The intelligent servo module for DIRECT SELECT receives the signals from the angle sensor which records the actual position of the range selector lever and eccentric shaft. The intelligent servo module for DIRECT SELECT controls the main motor and the emergency motor.
Flash programming
The intelligent servo module for DIRECT SELECT is flashable, i.e., the complete software for the intelligent servo module for DIRECT SELECT can be replaced (re-installed).
The software required for control unit programming can be found on the Star Diagnosis DAS Update DVD.
CAN data bus
The intelligent servo module for DIRECT SELECT is connected to the CAN connection of the vehicle via the drive train CAN (CAN C) and exchanges data with other control units.
The BAS release switch (A7/7s1) on Model 221 is replaced as of 2.6.09 and on model 216 as of 1.9.10 by the brake light switch (S9/1). With code (233) DISTRONIC PLUS and code (239) ART Plus Light, the BAS release switch is still used.
Input and output signals
The intelligent servo module for DIRECT SELECT evaluates the following input signals and outputs the appropriate output signals:
^ Direct input signals
^ Direct output signals
^ CAN input signals
^ CAN output signals
Direct input signals
- Terminal 30
- Circuit 31
- Power supply for emergency motor as emergency path
- None
CAN input signals
Front SAM control unit with fuse and relay module (N10/1)
- Feedback "Circuit 54 ON" (additional information for park pawl)
ESP control unit (N47-5)
- Wheel speeds
- Position of BAS release switch or brake light switch (for park pawl)
EIS [EZS] control unit (N73)
- Request to engage selector lever position "P or N"
Fully integrated transmission control unit (VGS) (Y3/8n4)
- Specified position of range selector lever
CAN output signals
Fully integrated transmission control unit (VGS) (Y3/8n4)
- Actual position of range selector lever (with "Circuit 15 ON")
Instrument cluster (A1)
- Gear selector switch position
The central gateway control unit (N93) is the interface between the chassis CAN (CAN E) and the central CAN (CAN F).
Shown in range selector lever position "N"
30 Main motor
31 Emergency motor
32 Slider
33 Worm shaft
34 Eccentric shaft
35 Range selector lever
36 Angle sensor
40 Eccentric shaft position sensor
41 Drive pulleys
42 Drive belt
Function
The main motor is actuated and the worm shaft is turned via the drive belt and the two drive pulleys. The carriage moves to the required position and the range selector lever assumes the specified position selected.
The actual position is recorded by the angle sensor and passed on to fully integrated transmission control unit (VGS) via the drive train CAN.
With "circuit 15 ON" the intelligent servo module for DIRECT SELECT forwards the gear selector switch position sent by the fully integrated transmission control unit (VGS) over the drive train CAN to the ME-SFI [ME] control unit (N3/10). The ME-SFI [ME] control unit sends a signal over the chassis CAN to the central gateway control unit and forwards it over the central CAN to the instrument cluster, which then actuates the gear indicator (A1p12).
With "Circuit 15 OFF" the intelligent servo module for DIRECT SELECT routes it through the steering column tube module over the chassis CAN and on routes the gear selector switch position over the drive train CAN to the instrument cluster, which then actuates the gear indicator. The signal path from the intelligent servo module for DIRECT SELECT to the gear indicator acts in this case just as with "Circuit 15 ON".
With "Circuit 15 OFF" and the vehicle at a standstill, selector lever position "P" or "N" is engaged as soon as the transmitter key (A8/1) is pulled out of the EZS control unit.
On vehicles with code (889) Keyless Go, the request for selector lever position "P", with "circuit 15 OFF" and the vehicle at a standstill is made as soon as the driver door is opened.
If selector lever position "N" is engaged before "Circuit 15 OFF" and the driver door is opened after "Circuit 15 OFF", selector lever position "N" remains engaged.
The ME-SFI [ME] control unit (N3/10) is the interface between the drive train CAN and the chassis CAN.
