Component description for intelligent servo module for DIRECT SELECT - GF27.19-P-4020GQH

TRANSMISSION 722.550 in MODEL 164.195 with ENGINE 272.973

Left view of transmission

Fig 1: Identifying Intelligent Servo Module For Direct Select

Courtesy of MERCEDES-BENZ USA

Location

The intelligent servo module is located on the left of the transmission housing.

Task

General

The gear "P", or from "P" into another gear as selected by the driver is not transferred via a rod (mechanical connection) from the control to the transmission but rather 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. The overall system is called "Shift-by-wire".

The intelligent servo module receives signals from the angle sensor, which records the actual positions of the range selector lever and the eccentric shaft. The intelligent servo module controls the main motor and the emergency motor.

CAN data bus

The intelligent servo module is connected to the CAN system of the vehicle via the engine compartment CAN (CAN-C) and exchanges data with other control units.

Input and output signals

The intelligent servo module 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

Direct output signals

None

CAN input signals

Front SAM control unit (N10)

Feedback "Circuit 54 ON" (additional information for park pawl)

Regenerative braking system control unit (N30/6)

Wheel speeds
Hybrid brake light switch position (S9/3) (for park pawl)

EIS [EZS] control unit (N73)

Request to engage gear selector switch position "P"

Hybrid vehicle fully integrated transmission controller unit (Y3/10)

Specified position of range selector lever

CAN output signals

Hybrid vehicle fully integrated transmission controller unit

Actual position of range selector lever (with "Circuit 15 ON")

Instrument cluster (A1)

Gear selector switch position "P"

Design

Shown in range selector lever position "N"

Fig 2: Identifying Range Selector Lever Position N

Courtesy of MERCEDES-BENZ USA

Function

The main motor is actuated and the toothed belt drive induce the threaded spindle to rotate. The carriage moves to the required position and the range selector lever assumes the specified position selected. The actual position is monitored by the angle sensor and sent over the engine compartment CAN to the ME-SFI [ME] control unit (N3/10) and then forwarded over the hybrid CAN CAN L) to the power electronics control unit (N129/1).

For "circuit 15 ON" the ME-SFI [ME] control unit routes the gear selector switch position sent by the power electronics control unit to the gear indicator (A1p12).

For "circuit 15 OFF" the ME-SFI [ME] control unit sends the gear selector switch position sent by the steering column tube module (N80) to the power electronics control unit to the gear indicator.

For "circuit 15 OFF" and when the vehicle is at a standstill the gear selector switch position "P" is engaged by the DIRECT SELECT intelligent servo module or "N" by the hybrid fully integrated transmission control unit (Y3/10) as soon as the transmitter key (A8/1) is removed from the EIS (EZS) control unit.

For vehicles with code (889) Keyless Go the request of gear selector switch position "P", with "circuit 15 OFF" and the vehicle at a standstill, takes place as soon as the driver door is opened.

If gear selector switch position "N" is engaged over the hybrid fully integrated transmission control unit before "circuit 15 OFF" and the driver door opened after "circuit 15 OFF", gear selector switch position "N" is engaged.

Wiring diagram for intelligent servo module (ISM) control unit

A80

PE27.60-P-2101-97MAA