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Eco Start/Stop Function Engine Management, Function - GF07.10-P-1042MRA

Engine 274.9 in model 205 (except 205.047/053/054/147/247/253) 

Engine 274.9 in model 253 (except 253.354/954) 

IMPORTANT The ECO start/stop function is subdivided into the engine-side and the on-board network side scope.

The ECO start/stop function engine management is seen from the engine management's point of view.

Function requirements for engine management, ECO start/stop function, general 

IMPORTANT The ME-SFI [ME] control unit (N3/10) detects the engine running via the evaluation of the crankshaft Hall sensor signals (B70). The ME-SFI [ME] control unit directly reads in the signals of the crankshaft Hall sensor.

IMPORTANT The front SAM control unit (N10/6) transmits the outside temperature via the interior CAN (CAN B), electronic ignition lock control unit (N73), suspension FlexRay (Flex E), powertrain control unit (N127) and drive CAN (CAN C1) to the ME-SFI [ME] control unit.

Engine management ECO start/stop function 

For a stationary vehicle, the ECO start/stop function switches the engine off automatically and starts it again as soon as the driver wishes to drive off or the system requests engine running. The fuel consumption and thus the exhaust emissions are reduced by cutting out the engine with the vehicle at a standstill.

It is still possible to stop and start the engine in the conventional way. The powertrain control unit permanently performs a system diagnosis and evaluates the system statuses for the ECO start/stop function.

All active systems that may be impaired by a shutoff engine constantly check their status. Once the status of a system permits an engine stop, this transmits its enable to the powertrain control unit.

The operational readiness of the ECO start/stop function is shown to the driver by the "ECO" symbol in the instrument cluster (A1).

The powertrain control unit transmits the request to activate the "ECO" symbol via the suspension FlexRay, electronic ignition lock control unit and user interface CAN (CAN HMI) to the instrument cluster.

The ECO start/stop function is activated and deactivated:

Model 205 up to model year 2019, model 253 

The lower control panel transmits the status of the ECO start/stop function push button switch to the powertrain control unit via the LCP-LIN (LINA3), Audio/COMAND control panel (A40/9), telematics CAN (CAN A), head unit (A26/17), user interface CAN, electronic ignition lock control unit, and suspension FlexRay.

Model 205 from model year 2019 

The lower left control panel transmits the status of the ECO start/stop function push button switch to the powertrain control unit via the LCP-LIN, Audio/COMAND control panel (except code 446 (touchpad only)) or touchpad (A105) (with code 446 (touchpad only)), telematics CAN, head unit, user interface CAN, electronic ignition lock control unit, and suspension FlexRay.

The ECO start/stop function comprises the following functions:

Automatic engine stop 

The engine is shut off, if all the following requirements are fulfilled:

The powertrain control unit transmits the enable for engine stop via the drive CAN to the ME-SFI [ME] control unit. The ME-SFI [ME] control unit transmits the status via the drive CAN to the powertrain control unit.

IMPORTANT After an automatic engine stop, a maximum of three automatic engine stops are permitted without exceeding a speed of 8 km/h in model 205 up to model year 2019 and model 253. For model 205 as of model year 2019, a maximum of one automatic engine stop is allowed.

After that, it is required to exceed the speed of 8 km/h.

When opening the engine hood in the automatic engine stop, the ECO start/stop function is switched off.

The engine must then be started by the driver.

IMPORTANT A warning tone is output if the engine was shut off by the ECO start/stop function and the driver exits the vehicle. In addition, the message "Veh. is operational, switch off ignition before exiting vehicle" appears in the instrument cluster. The ignition is switched off automatically after one minute.

Automatic engine start 

The engine is started automatically under the following conditions:

IMPORTANT A maneuvering process is recognized for an engaged reverse gear and the ECO start/stop function is deactivated. If the engine is stopped it is force started by the system and the engine stop function is suppressed if it is running. The ECO start/stop function is subsequently activated again for an engaged gear range D and for exceeding a vehicle speed of 15 km/h.

IMPORTANT Engine 274.9 in model 205 (except 205.047/053/054/147/247/253) with transmission 722.9

Engine 274.9 in model 205 (except 205.053/054/253) with transmission 725.0

Engine 274.9 in model 253 (except 253.354/954) with transmission 725.0

Upon activation of the Sport Plus mode, the ECO start/stop function is deactivated.

Forced engine start (start dictated by the system) 

To ensure the on-board electrical system stability and the function of the safety-relevant systems, the engine can be force started.

The engine is started if the on-board electrical system is, for example, loaded or a function or stop requirement is no longer fulfilled.

If the on-board electrical system stability can subsequently still not be ensured, the ECO start/stop function is switched off and the engine is no longer shut off.

The following events also lead to a forced engine start:

  Electrical function schematic for engine management, ECO start/stop function   PE07.10-P-2724-97FBA
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