Engine timing start-stop function - GF07.10-P-1041MMS

ENGINE 157.9 in MODEL 212, 218 as of model year 2014 with CODE B03 (ECO start/stop function) 

ENGINE 278.9 in MODEL 207, 212, 218 as of model year 2014 with CODE B03 (ECO start/stop function) 

The "Engine management, start/stop function" subfunction is examined from the point of view of the engine management. Information for partial function "Energy management, start/stop function" is documented in the function description "Energy management function".

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

• Engine running at operating temperature (coolant temperature: 60°C < 115°C).
• Speed of 15 km/h exceeded once during forward travel
• Engine hood closed
• Gear range "D" or "N"
• System diagnosis completed

Engine management start-stop function, general 

With a stationary vehicle, the 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) continuously performs a system diagnosis and assesses the function requirements for the start/stop function.

The front SAM control unit with fuse and relay module (N10/1) also checks the function of all involved components and transmits the status to the ME-SFI [ME] control unit via the chassis CAN 1 (CAN E1).

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).

For the start-stop function the ME-SFI [ME] control unit reads in the following sensors and signals:

• Coolant temperature sensor (B11/4) (model 207, 212), coolant temperature sensor (B11/4) (model 218)
• Accelerator pedal sensor (B37), accelerator pedal actuation
• Crankshaft Hall sensor (B70), engine rpm
• IC, vehicle speed via chassis CAN 1 and chassis CAN 2 (CAN E2)
• 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
  • Signal engine hood closed (with code U60 (Pedestrian protection))
• Front SAM control unit with fuse and relay module:
  • A/C status
  • Engine stop prohibition
  • Engine start request
  • Contact switch signal at the front left
  • ECO start/stop function button (N72/1s50) status
  • Signal engine hood closed (with code 551 (Anti-theft alarm system (ATA) or model 204)
• Electronic Stability Program control unit (N30/4) or Electronic Stability Program Premium control unit (N307) (for code 233 (DISTRONIC PLUS), via the chassis CAN 1:
  • Brake actuation
  • Wheel speed
  • Engine start request
  • Engine stop release
  • Engine stop prohibition
• AIRmatic control unit (N51/3) (for model 212, 218 with code 489 (AIRMATIC (air suspension with continuous variable damping)) via chassis CAN 1
  • Engine stop prohibition
  • Engine start request
• Adaptive damping system control unit (N51/5) (for model 207 with code 483 (ADVANCED AGILITY package), vehicle level via the chassis CAN 1
• Radar sensors control units (N62/1) (for model 207, 212 as of model year 2014 with code 23P (Driving Assistant Package Plus), model 218 as model year 2015 with code 23P (Driving Assistant Package Plus)), engine torque request (raising or reducing) via chassis CAN 1
• Video and radar sensor system control unit (N62/2) (for model 218 up to model year 2015 with code 233 (DISTRONIC PLUS, with code 237 (Active Blind Spot Assist), with code 238 (Active Lane Keeping Assist), engine torque request (increasing or reducing) via the chassis CAN 1
• Steering column tube module control unit (N80), steering wheel angle and steering wheel angular velocity via chassis CAN 1
• Rear axle electronic level control system control unit (N97) (model 212.2 except code 489 (AIRmatic air suspension with continuous variable damping) vehicle level via chassis CAN 1
• Fuel system control unit (N118), fuel pressure via the drive train CAN (CAN C)
• Fully integrated transmission control controller unit (Y3/8), status of gear range via drive train CAN

Engine management Start-Stop function, function sequence 

The 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 on the ECO start/stop function button lights up.
• Vehicle speed = 0 km/h
• Coolant temperature >60°C and <115°C
• Transmission oil temperature > 10°C and < 120°C
• Engine oil temperature in the specified value range
• Engine rpm in specified value range
• Gear range "D" or "N"
• Accelerator pedal not operated
• Service brake actuated up to standstill of the vehicle
• Adequate vacuum in the brake booster
• No control intervention function from AIRMATIC, brake assistance and distance regulation system
• Engine hood closed
• No crash signal
• Steering wheel angle a maximum of 210°
• Steering wheel angular velocity in the specified value range
• Outside temperature in range
• Condition of the on-board electrical system OK
• Driver door closed
• Driver seat belt applied
• Interior temperature regulated

After an automatic engine stop a maximum of three automatic starts 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 for the engine to be stopped again.

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 (N10/1kM) 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 function requirements occurs:

• Condition of the on-board electrical system not OK
• Coolant temperature >115°C
• Exceeding of the engine stop period of a maximum of 3 minutes
• Change in the status of the A/C
• AIRmatic, brake assist or distance regulation system in control intervention function mode
• A brake application cannot be safely completed once initiated.
• The vacuum in the brake booster is not adequate
• Driver absence detected
• Change of the steering wheel angle by more than 8°
• Vehicle speed > 2 km/h
• Communication error of the ECO start/stop function with one of the following systems: suspension and steering functions, energy management, brake and management systems

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, and if it is running the engine stop function is suppressed.

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.

		MODEL 207	PE07.10-P-2722-97EAK
		MODEL 212	PE07.10-P-2722-97DAQ
		MODEL 218	PE07.10-P-2722-97XAI
	Overview of system components for gasoline injection and ignition system with direct injection	ENGINE 157.9 in MODEL 212, 218 as of model year 2014 with CODE B03 (ECO start/stop function) ENGINE 278.9 in MODEL 207, 212, 218 as of model year 2014 with CODE B03 (ECO start/stop function)	GF07.70-P-9998MM