ECO Start/Stop Function Engine Management, Function - GF07.10-P-1042MMY

Engine 157.9, 276.8, 278.9 in MODEL 166 (except 166.063) 

as of model year 2016 

Engine 157.9, 276.8, 278.9 in MODEL 292 

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" partial function is seen from the point of view of the Engine management.

Information for the partial function "ECO start/stop function energy management" is documented in the function description "Energy management function".

Function requirements ECO start/stop function, general points 

• Circuit 15 (ignition ON)
• Circuit 87 M (Engine management ON)
• Engine runs
• Outside temperature between -10°C and 40°C
• System diagnosis complete and fault-free
• Speed of 8 km/h exceeded once during forward travel
• Speed of 15 km/h exceeded once during forward travel after a maneuvering process

ECO start/stop function, general points 

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. The fuel consumption and thus the exhaust emissions are reduced by cutting out the Engine with the vehicle at a standstill.

Conventional cutting out and starting of the Engine with the transmitter key (A8/1) or via the KEYLESS-GO start/stop button (S2/3) (with code 889 (Keyless-Go) continues to be possible.

The ME-SFI [ME] control unit (N3/10) permanently performs a system diagnosis and assesses the system conditions for the ECO start/stop function.

All systems involved in the ECO start/stop function continuously check their status, and transmit this via the interior CAN (CAN B), the electronic ignition lock control unit (N73) and chassis CAN 1 (CAN E1) to the ME-SFI [ME] control unit.

If the function requirements are fulfilled, the driver is notified of ECO start/stop function readiness by the "ECO" symbol in the multifunction display (A1p13) in IC (A1).

Function sequence for ECO start/stop function 

The ECO start/stop function consists of the following partial functions:

• Function sequence for automatic Engine stop 
• Function sequence for automatic Engine start 
• Function sequence for forced Engine start (a start dictated by the system) 

Function sequence for automatic Engine stop 

The Engine is switched off by the ME-SFI [ME] control unit if all of the following function requirements are fulfilled:

• Indicator lamp for the ECO start/stop function button (N72/1s50) lights up (system is fault-free and ECO start/stop function is activated)
• Vehicle speed = 0 km/h
• Coolant temperature between 60°C and 115°C
• Transmission oil temperature between 10°C and 120°C
• Engine rpm in specified value range
• Gear range "D" or "N"
• Accelerator pedal not operated
• Service brake actuated up to standstill of the vehicle
• Sufficient vacuum in the brake booster (residual pressure in the brake booster does not fall below -200 mbar)
• Engine hood closed
• No crash signal
• No emergency braking initiated
• steering wheel angular velocity in the specified value range
• Condition of the on-board electrical system OK
• Driver door closed
• Driver seat belt applied
• Interior temperature regulated
• Switch off off-road programs

The ME-SFI [ME] control unit reads in the following signals for checking the function requirements:

• Coolant temperature sensor (B11/4), coolant temperature
• Accelerator pedal sensor (B37), accelerator pedal actuation
• Crankshaft Hall sensor (B70), Engine rpm
• Instrument cluster, vehicle speed via chassis CAN 2 (CAN E2), the electronic ignition lock control unit and chassis CAN 1
• Supplemental restraint system control unit (N2/10), direct crash signal
• Supplemental Restraint System control unit via chassis CAN 1:
  • Indirect crash signal
  • Status of driver seat belt
  • Engine hood signal closed (for code U60 (Active Engine hood (pedestrian protection)))
• SAM control unit (N10) via the interior CAN, the electronic ignition lock control unit and chassis CAN 1:
  • Engine stop prohibition
  • Engine start request
  • Signal Engine hood closed (with code (551) Anti-theft alarm system (ATA [EDW]))
• Automatic air conditioning control and operating unit (N22/7) via interior CAN, electronic ignition lock control unit and chassis CAN 1:
  • A/C status
  • Engine stop prohibition
  • Engine start request
• Electronic Stability Program control unit (N30/4) via chassis CAN 1:
  • Brake actuation
  • Wheel speed
  • Engine start request
  • Engine stop release
  • Engine stop prohibition
• AIRMATIC control unit (N51/3) via chassis CAN 1 (for CODE 489 (AIRMATIC)):
  • Engine stop prohibition
  • Engine start request
• Left front door control unit (N69/1), front left contact switch signal via the interior CAN, the electronic ignition lock control unit and chassis CAN 1
• Radar sensors control unit (N62/1) (for CODE 23P (Driving Assistance Package)), Engine torque request (increase or reduction) via the chassis FlexRay (Flex E), the chassis gateway control unit (N93/7) (with CODE 23P (Driving Assistance Package)) and chassis CAN 1
• Upper control panel control unit (N72/1), status of the ECO start/stop function button via the battery sensor LIN (LIN B15), the interior CAN and chassis CAN 1
• Steering column tube module control unit (N80), via chassis CAN 1
  • Steering wheel angle
  • Steering wheel angular velocity
• Fuel system control unit (N118), fuel pressure via the drive train CAN (CAN C)
• Fully integrated transmission control unit (Y3/8n4), status of gear range via drive train CAN

After an automatic Engine stop a maximum of three automatic Engine stops are permitted without exceeding the speed threshold of 8 km/h.

After the fourth Engine start, the vehicle must exceed a speed of 8 km/h in the Engine stop.

Upon opening of the Engine hood in automatic Engine stop, the ECO start/stop function is switched off and all indicator lamps in the IC light up. The Engine must be restarted using the transmitter key or over the start/stop button KEYLESS-GO (for code 889 (Keyless-Go).

Function sequence for automatic Engine start 

The Engine is started automatically for actuation of the accelerator pedal.

The ME-SFI [ME] control unit actuates the circuit 50 starter relay (F58kM) with a ground signal. The power contact on the relay closes and the starter solenoid switch (M1) is supplied at "circuit 50" with a voltage from "circuit 30".

The fuel system control unit receives the CAN signal "Fuel specified pressure" from the ME-SFI [ME] control unit via the drive train CAN and actuates the fuel pump (M3) with a pulse width modulated signal accordingly.

Function sequence for forced Engine start (a start dictated by the system) 

The forced Engine start subfunction is available as a protection function. Here the Engine is force started autonomously (without any action taken by the driver) by the ME-SFI [ME] control unit if one of the following start requirements occurs:

• On-board network condition requires the Engine to run.
• Coolant temperature > 115°C
• Exceeding of the Engine stop period of a maximum of 3 minutes
• A/C required Engine running (e.B. windshield fogged up)
• Vacuum on the brake booster not in the nominal range (residual pressure in the brake booster does not fall below -200 mbar)
• Driver presence recognition (driver seat belt or driver door is opened)
• Change of the steering wheel angle by more than 8°
• Vehicle speed >2 km/h for forward travel and immediately for recognition of rolling backwards
• System or communication error of one of the following systems or components: driver presence, steering, on-board electrical system, brake system, accelerator pedal, transmission, starter, Engine

A maneuvering process is recognized for an engaged gear range "R" 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.

The Engine is also started if the driver door is opened, the driver seat belt buckle is opened or the ECO start/stop function is switched off via the ECO start/stop function button.

	Electrical function schematic for Engine management, ECO start/stop function		PE07.10-P-2724-97NBG
	Overview of system components for gasoline injection and ignition system with direct injection	Engine 276.8 in MODEL 166 (except 166.063) as of model year 2016 Engine 276.8 in MODEL 292	GF07.70-P-9998MMX
		Engine 157.9, 278.9 in MODEL 166 as of model year 2016 Engine 157.9, 278.9 in MODEL 292	GF07.70-P-9998MNG