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Gear Shift, Function - GF27.60-P-2000AHG

Transmission 722.9 in model 463 as of model year 2013 

Function requirements, general 

IMPORTANT The CDI control unit (N3/9) (diesel engine) or the ME-SFI control unit (N3/10) (gasoline engine) sends the "engine running" signal via the drivetrain CAN (CAN C) to the fully integrated transmission control unit (Y3/8n4) and to the intelligent servo module for DIRECT SELECT (A80).

Shift operation, general 

The fully integrated transmission control controller unit (Y3/8) converts the electrical signals coming from the fully integrated transmission control unit into hydraulic signals. The shift operation is implemented by activating and deactivating the corresponding multidisk clutches and multidisk brakes via the control solenoid valve.

The gear ranges "R", "N", "D" can be selected by the DIRECT SELECT INTERFACE (N150). The "P" function (park pawl) is executed at speeds v < 8 km/h by pressing the park pawl button (S76/14) which is read in directly by the DIRECT SELECT INTERFACE. This transmits the desired gear range via the drivetrain CAN to the fully integrated transmission control unit and to the intelligent servo module for DIRECT SELECT.

The intelligent servo module for DIRECT SELECT changes the position of the selection range lever, which is forwarded mechanically to the selection range sensor (Y3/8s1).

Although the shift range can be changed in the forward gears while driving, the fully integrated transmission control unit prevents a shift operation if the engine speeds are too high or too low.

The fully integrated transmission control unit actuates the following control solenoid valves directly:

The fully integrated transmission control unit reads in the signals from the following sensors directly:

In addition, the CDI control unit (diesel engine) or the ME-SFI control unit (gasoline engine) requires the following information:

The fully integrated transmission control unit sends this information via the drivetrain CAN to the CDI control unit (diesel engine) or to the ME-SFI control unit (gasoline engine).

Messages and displays in instrument cluster (A1): 

Information on the selected gear, on the set shift range, on the gear range or on the transmission mode is displayed in the instrument cluster. The fully integrated transmission control unit sends the corresponding request via the drivetrain CAN, CDI control unit (engine 642) or ME-SFI control unit (engine 157, 273) or powertrain control unit (N127) (engine 176), chassis CAN 1 (CAN E1), electronic ignition lock control unit (N73) and chassis CAN 2 (CAN E2) to the instrument cluster.

The instrument cluster then actuates the following displays directly:

The shift mechanism function comprises the following subfunctions:

Additional function requirements for limiting shift range and shifting to optimum gear 

IMPORTANT The DIRECT SELECT INTERFACE reads in the status of the A/T transmission mode button (S16/12) directly and sends it via the drivetrain CAN to the fully integrated transmission control unit.

Function sequence for limiting shift range and shifting to optimum gear 

Limiting shift range: 

A limited shift range allows the braking effect of the engine to be used on downhill gradients and prevent unwanted upshifting on steep passes or in mountainous terrain.

The "shift range limitation" function is activated by pressing the steering wheel downshift button (S110/1) once. If the engine speed permits, the automatic transmission shifts down a gear and limits the shift range to the respective gear.

By pressing the steering wheel upshift button (S111/1) with the shift range limitation function active, the automatic transmission shifts up a gear and limits the shift range to the respective gear.

Pressing and holding down the upshift steering wheel gearshift button cancels the shift range limitation function completely. The automatic transmission changes directly to "D".

The steering wheel electronics (N135) read in the signals from the steering wheel gearshift buttons directly and sends them via the steering LIN (LIN E1) to the steering column tube module control unit (N80). The steering column tube module control unit sends the signals via chassis CAN 1, the CDI control unit (engine 642) or ME-SFI control unit (engine 157, 273) or powertrain control unit (engine 176) and drivetrain CAN to the fully integrated transmission control unit.

IMPORTANT The set shift range is shown in the multifunction display.

IMPORTANT Depending on the transmission mode selected, different long or short gear ranges (shifting at low or high engine speed) as well as drive torques adapted to the operating condition are available when starting off in a forward and backward direction.

Shifting to optimum gear: 

The "shift to optimum gear" function allows direct shifting to the gear in which the vehicle can best be accelerated to decelerated (by the braking effect of the engine). For this purpose, the automatic transmission shifts down by one or more gears.

The function is activated by pressing and holding down the steering wheel downshift button.

IMPORTANT When shifting down, the automatic transmission shifts only as far as the second gear. In order to shift into the first gear, the steering wheel downshift button must be pressed again.

Additional function requirements for manual upshift and downshift (except code ZU8 (USA national version) and as of model year 2015 except code 990 (AMG vehicle documents/identification plate control)) 

IMPORTANT The DIRECT SELECT INTERFACE reads in the status of the A/T transmission mode button directly and sends it via the drivetrain CAN to the fully integrated transmission control unit.

Function sequence for manual upshift and downshift (except code ZU8 (USA national version) and as of model year 2015 except code 990 (AMG vehicle documents/identification plate control)) 

In the manual transmission mode "M", gears 1 to 7 can be directly shifted using the steering wheel downshift button and the steering wheel upshift button.

The steering wheel electronics read in the signals from the steering wheel gearshift buttons directly and sends them via the steering LIN to the steering column tube module control unit. The steering column tube module control unit sends the signals via chassis CAN 1, the CDI control unit (engine 642) or ME-SFI control unit (engine 157, 273) or powertrain control unit (engine 176) and drivetrain CAN to the fully integrated transmission control unit.

IMPORTANT In the manual transmission mode "M", the automatic transmission does not shift up by itself even if the maximum governed RPM of the engine is reached.

If the vehicle slows down or is stopped without manual downshift, the automatic transmission shifts down automatically. When the vehicle is stationary the transmission automatically shifts into 1st gear. It is possible to start off both in 1st or 2nd gear.

  Electrical function schematic for shift operation   PE27.19-P-2057-97ZGA 
  Overview of system components for automatic transmission (AT)   GF27.10-P-9992AHG 
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