Mercedes Benz 216 Automatic transmission Control Unit

Two different transmissions will be available for the new CL-Class on its market launch depending on the model:
• CL 500 with 7-speed automatic transmission
• CL 600 with 5-speed automatic transmission
Instead of the previous electronic selector lever module (ESM) on the center tunnel there is now a DIRECT SELECT gear selector switch located near the steering wheel and DIRECT SELECT steering wheel shift buttons.
· 1 Transmission
· A80 Intelligent servo module for DIRECT SELECT
· Y3/8n4 Fully integrated transmission control (VGS) control unit
Automatic transmission 722.904 is an electronically controlled 7-speed automatic transmission with a lockup clutch in the torque converter.
The transmission has 7 forward gears and 2 shifted reverse gears.
The difference between this and conventional transmission control systems is in its full integration, as characterized by the following features:
• Integration of all functions and components of the transmission in one installation module
• Integration of this module in the automatic transmission
• Minimization of interfaces with the wiring harness
The fully integrated transmission control (VGS) control unit is installed in the oil pan of the automatic transmission.
By being bathed in transmission oil, the control unit is constantly kept cool.
The fully integrated transmission control (VGS) control unit monitors and shifts the transmission depending on:
• Vehicle speed
• Load condition of the vehicle
• Driving resistance
• Accelerator pedal position and actuation rate
• Selector lever position
• Transmission mode selection C/S/M
• Drive train CAN signals
Automatic transmission 722.649 is an electronically controlled 5-speed automatic transmission with a lockup clutch in the torque converter. The gear ratios for the gear settings are realized by 3 planetary gear sets.
The transmission has 5 forward gears and 2 shifted reverse gears. The 5th gear is an overdrive gear.
The shifts are actuated electronically and the drive positions are shifted by means of 3 hydraulically actuated multidisk brakes, 3 hydraulically actuated multidisc clutches and 2 mechanical freewheels.
The electrohydraulic controller unit consists of a light alloy shift plate for the electric controller unit. This is composed of a plastic support in which all the electrical components are integrated. The support is bolted onto the shift plate.
The ETC control unit monitors and shifts the automatic transmission depending on:
• Vehicle speed
• Accelerator pedal position and actuation rate
• Position of the DIRECT SELECT gear selector switch
• Transmission mode selection C/S/M
• Drive train CAN signals
Note
The ETC [EGS] control unit (N15/3) with the 5- speed automatic transmission 722.649 is installed only in combination with engine 275.
In the new CL-Class the drive position command is transmitted via the operating lever of the DIRECT SELECT gear selector switch over an electrical link to the automatic transmission.
The DIRECT SELECT gear selector switch for the drive positions P, R, N or D is located on the right side of the steering column module and can be operated from the steering wheel.
On the rear of the steering wheel there are additional shift buttons on both sides installed in the steering wheel spokes. These shift buttons can be used to shift up and down the individual gears manually.
The right shift button in the steering wheel shifts up and the left shift button shifts down. For this the transmission mode M (manual) must be selected and drive position D must be engaged.
Servo module
The intelligent servo module (ISM) for DIRECT SELECT (A80) is mounted on the left side of the automatic transmission in the direction of travel.
It allows the system to read the selected drive position via electrical signals and to engage the drive position via a mechanical interface on the transmission.
Function sequence
The DIRECT SELECT gear selector switch on the steering column module engages the desired drive position and directs it by means of electrical signals via the ME engine control unit to the intelligent servo module for DIRECT SELECT.
The servo module reads the request and checks the plausibility of the selected drive position. If the drive position is plausible, it is engaged by an actuator motor on the transmission.
The signal for the selected transmission stage P, R, N or D, or for the individual gears, is relayed onto the chassis CAN by the steering column module and read by the ME-SFI [ME] engine control unit.
At the same time, the appropriate signal is transmitted to the central gateway control unit over the chassis CAN. This forwards the signal onto the central CAN and on to the instrument cluster. The instrument cluster displays the preselected transmission stage or the selected gear.
The signal read by the ME-SFI [ME] engine control unit is forwarded onto the drive train CAN to the ETC control unit.
The ETC control unit checks the plausibility of the signal for the preselected shift command.
If the signal passes the plausibility check, the ETC control unit sends the signal to implement the preselected shift operation to the DIRECT SELECT intelligent servo module. The DIRECT SELECT intelligent servo module implements the shift command via a mechanical interface in the transmission.
· 1 Gear preselection
· 2 Display preselection
· 3 Engage gear
· A1 Instrument cluster
· A80 Intelligent servo module for DIRECT SELECT
· N3/10 ME-SFI [ME] control unit
· N15/3 ETC [EGS] control unit
· N80 Steering column module
· N93 Central gateway control unit
· S16/13 DIRECT SELECT gear selector switch
· S110/1 Steering wheel gear shifter MINUS
· S111/1 Steering wheel gear shifter PLUS
· C Drive train CAN
· E Chassis CAN
· F Central CAN

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