(Engine Timing Start-Stop Function - GF07.10-P-1041OGR)

Engine 642.8 in MODEL 166

up to model year 2016

with CODE B03 (ECO start/stop function)

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

The " Engine timing, 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 ECO start/stop function, general points

Engine runs
Outside temperature in the range: -10°C > T < 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

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

The CDI control unit (N3/9) continuously performs a system diagnosis and assesses the system conditions for the ECO start/stop function. All systems participating on the ECO start/stop function permanently check their status and transmit this via the chassis CAN 1 (CAN E1) or drive train CAN (CAN C) to the CDI control unit.

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

ECO Start-stop function, function sequence

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 CDI control unit if all of the following function requirements are fulfilled:

Vehicle speed = 0 km/h
Coolant temperature ≥ 70°C at an outside temperature of -30°C to -10°C
Coolant temperature ≥ 60°C at an outside temperature of -9°C to 14°C
Coolant temperature of ≥ 15°C at an outside temperature of 15°C to 60°C
Coolant temperature < 110°C
Engine oil temperature between 15°C and 120°C
Engine rpm in specified value range
Transmission oil temperature between 10°C and 120°C
Gear range "D" or "N"
Accelerator pedal not operated
Service brake actuated up to standstill of the vehicle
Atmospheric pressure > 760 mbar
Sufficient vacuum (-1150 mbar to 130 mbar) in brake booster
Engine hood closed
No crash signal
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
Fill level in fuel tank > 2 l
Do not overload diesel particulate filter
Off-road program disabled
No previous maximum full-stop braking

For the start-stop function the CDI control unit reads in the following signals:

Engine oil temperature sensor (B1)
Left fuel tank fuel fill level sensor fuel level indicator (B4/1)
Right fuel tank fuel level indicator fill level sensor (B4/2)
Coolant temperature sensor (B11/4)
Accelerator pedal sensor (B37), accelerator pedal actuation
DPF differential pressure sensor (B28/8) (with code 474 (Particulate filter))
Fuel temperature sensor (B50), fuel temperature
Crankshaft Hall sensor (B70), Engine rpm
Instrument cluster (A1), vehicle speed via chassis CAN 2 (CAN E2), electronic ignition lock control unit (N73) and chassis CAN 1 (CAN E1)
Supplemental restraint system control unit (N2/10), direct crash signal
Steering column module control unit, via chassis CAN 1:
Indirect crash signal
Status of driver seat belt
SAM control unit (N10) via interior CAN (CAN B), the electronic ignition lock control unit and chassis CAN 1
Engine stop prohibition
Engine start request
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
Wheel speed
Brake actuation
Engine stop prohibition
Engine stop release
Engine start request
AIRmatic control unit (N51/3) via chassis CAN 1 (with code 489 (AIRmatic) (Air suspension with level adjustment and adaptive damping system ADS))
Engine stop prohibition
Engine start request
Video and radar sensor system control unit (N62/2) via chassis CAN 1 (with code 233 (DISTRONIC PLUS), code 237 (Active Blind Spot Assist) and code 238 (Active Lane Keeping Assist))
Engine torque increase request
Engine torque reduction request
Left front door control unit (N69/1) via interior CAN (CAN B), electronic ignition lock control unit and chassis CAN 1
Engine stop prohibition
Driver door closed
Steering column tube module control unit (N80), via chassis CAN 1
Steering wheel angle
Steering wheel angular velocity
FESCUE (N118), fuel pressure via the drive train CAN
Fully integrated transmission control controller unit (Y3/8), engaged gear range over 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 for the Engine to be stopped again.

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 (with code 889 (Keyless Go)).

Function sequence for automatic Engine start

The Engine is automatically started upon releasing the brake or actuating the accelerator pedal. The CDI control unit actuates the circuit 50 starter relay (F58kM) by means of 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 "Specified fuel pressure" over the drive train CAN from the CDI control unit and actuates the fuel pump (M3) accordingly using a pulse width modulated signal.

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 CDI control unit if one of the following function requirements occurs:

On-board network condition requires the Engine to run
Coolant temperature > 125°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 BAS brake booster not in the nominal range (-1150 mbar up to 130 mbar)
Driver presence recognition
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 in one the following systems: driver presence, steering, on-board electrical system, brake and management systems, accelerator pedal, transmission, starter, Engine, chassis

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 forward gear and for exceeding a vehicle speed 15 km/h.

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

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