Component Description For Intelligent Servo Module For Direct Select - GF27.19-P-4020AHA

TRANSMISSION 722.9 in MODEL 166 up to model year 2016

View of automatic transmission (without CODE 430 (On & Offroad package)) from left

Fig 1: Intelligent Servo Module For Direct Select Component Location - Transmission 722.9 In Model 166

Courtesy of MERCEDES-BENZ USA

Location

The intelligent servo module for DIRECT SELECT is mounted on the left of the transmission housing in the direction of travel.

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 lever (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 control unit's complete software can be exchanged (replaced) with Xentry Diagnostics. The software required for control unit programming can be found on the diagnostic system software DVD.

CAN 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.

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

Direct output signals

None

CAN input signals

SAM control unit (N10):

Feedback "Circuit 54 ON" (additional information for park pawl) Electronic Stability Program control unit (N30/4):
Wheel speeds
Status of service brake

Electronic ignition lock control unit (N73):

Request to engage selector lever position "P or N"

Fully integrated transmission control unit (Y3/8n4):

Specified position of range selector lever

Transfer case control unit (N15/7):

"N" gear range request

CAN output signals

Fully integrated transmission control unit (Y3/8n4):

Actual position of range selector lever (with "Circuit 15 ON") Instrument cluster (A1):
Driving stage engaged

The CDI control unit (N3/9) (with diesel engines) or ME-SFI [ME] control unit (N3/10) (with gasoline engines) is the interface between the drive train CAN and the chassis CAN 1 (CAN E1).

Shown in range selector lever position "N"

Function

The main motor is actuated and the threaded rod is turned by 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 detected by the angle sensor and sent via the drive train CAN to the fully integrated transmission control unit. At "circuit 15 ON" the intelligent servo module for DIRECT SELECT sends the signal for the currently engaged gear range to the CDI control unit or the ME-SFI [ME] control unit. The CDI control unit or the ME-SFI [ME] control unit sends the signal over the chassis CAN 1 to the electronic ignition lock control unit and further over the chassis CAN 2 (CAN E2) to the instrument cluster, which actuates the gear indicator (A1 p12) t. At "Circuit 15 OFF" the intelligent servo module for DIRECT SELECT sends the selector lever position from the steering column tube module control unit (N80) over chassis CAN 1 and further through the drive train CAN top 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 vehicle standstill, selector lever position "P" or "N" is engaged, as soon as the transmitter key (A8/1) is removed from the electronic ignition lock 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 CDI control unit or the ME-SFI [ME] control unit is the interface between the drive train CAN and chassis CAN 1. The electronic ignition lock control unit is the interface between chassis CAN 1 and chassis CAN 2.

	Wiring diagram for fully integrated transmission control unit		PE27.19-P-2103-97NAA
	Wiring diagram for intelligent servo module (ISM) control unit		PE27.60-P-2101-97NAA