ECO start/stop function

Service Technology Guide

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 Mercedes-Benz Service

ECO start/stop function

Service Technology Guide

Daimler AG · Retail Operations (GSP/OR) · D-70546 Stuttgart

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 Preamble4
Preface4

Introduction5
Overview of ECO start/stop function 5
ECO display concept 8

System description 10
Function principle of ECO start/stop function 10

Function description 17
Function groups 07 and 54 17
Energy management of ECO start/stop function with additional battery 18
Function sequence for engine stop 19
Function sequence for engine start 20
Function sequence for forced engine start 21
Illustrations of the power supply principle 22
State of ECO start/stop function additional battery 24
Charging the ECO start/stop function additional battery 25
Other components and functions 26

Stop prohibitions and stop inhibitors 31

Stop prohibitions and stop inhibitors 31

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 Diagnosis in Xentry Diagnostics 32
Stop prohibition system analysis 32
Stop inhibitor system analysis 34
Stop inhibitor system analysis (manual selector) (ECO start/stop indicator green) 35
System analysis in Xentry Diagnostics, overview 36
Read out circular buffer 38
Read out fault status of ECO start/stop function 40
Fault status of ECO start/stop function (STORED)  41
Read out causes for engine stop inhibit 42
Requirements for automatic engine start 43
Engine stop inhibit (components) 44
Diagnosis of ECO start/stop function via actual values of electrical system data 46
Read out actual values of “Components” 49
ECO start/stop function diagnosis tree 51

Notes/fault profiles 52
Notes/fault profiles 52
Notes/fault profiles 53
Checklist for ECO start/stop function 55

Annex56
Abbreviations56
Index57
Information and copyright 58

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Preface

Dear Reader,
This Technology Guide is intended to provide you with an This Technology Guide acts as an aid for the repair and the
overview of the ECO start/stop function and its functions in diagnosis of technical problems. For such needs, the WIS and
the current passenger car model series (except hybrid model Xentry Diagnostics systems are available as usual.
series).
We will publish modifications and new features in the relevant
The purpose of this information is to provide technicians, fit- WIS documents only. The information presented in this bro-
ters and service advisor at the service operations with a link chure may therefore differ from the information published in
between the Introduction into Service manuals and the more the WIS.
detailed information in the Workshop Information System
(WIS) and Xentry Diagnostics. All the information relating to technical data in this brochure
is valid as of the copy deadline on 01.11.2014 and may the-
The contents focus on the following topics: refore differ from the current production configuration.
• System and function description
• Diagnosis Daimler AG
Retail Operations (GSP/OR)

bbNote
Wherever possible, the images in this brochure have
been designed to be language-neutral. If this was not
possible, German or English texts appear in exceptio-
nal cases.

bbNote bbNote
The printed documents are now available in WIS via Information about the vehicles and about operating
WIS Service Media. the vehicle functions can also be found in the interac-
tive owner's manual on the Internet.

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 Overview of ECO start/stop function

Introduction
P15.00-2207-00
System overview of ECO start/stop function illustrated on model series 205 with manual transmission

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 Introduction

6
System overview of ECO start/stop B79/3 Manual transmission main N30/4 Electronic Stability Program
function shifter shaft position sensor control unit
1 Starter-alternator wiring G2 Alternator N72/5s 2ECO start/stop function
harness K40/8 Engine fuse and relay module button
2 Battery line M1 Starter N80 Steering column tube module
3 Neutral badge on shift lever M42 Electric transmission oil control unit
knob pump R62 Voltage dip limiter
A1 Instrument cluster N3/9 CDI control unit S62/42 Right engine hood contact
B38/2 Rain/light sensor with additio N3/10 ME-SFI [ME] control unit switch
nal functions N10/6 Front SAM control unit S62/43 Left engine hood contact
B53/1 Clutch pedal sensor N10/8 Rear SAM control unit switch
B64/1 Brake vacuum sensor N22/1 Climate control control unit
B70 Crankshaft Hall sensor
Overview of ECO start/stop function

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ECO start/stop function | Service Technology Guide
 Overview of ECO start/stop function

Introduction
The designation “ECO” stands for “Engine Cut Off”.
The ECO start/stop function ensures that the engine is The ECO start/stop function is activated each time the en-
switched off automatically at low speeds and under certain gine is started with the key. The system is ready to operate
conditions. automatically when the ECO symbol is shown in the multifun-
ction display or is highlighted in green in vehicles with color
The engine then restarts automatically to drive off again. display.
In this way, the ECO start/stop function helps to reduce the
fuel consumption and the exhaust emissions of the vehicle. The ECO start/stop function can be switched on and off via
the ECO switch. The function is reactivated at the next key
start.

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 ECO display concept
Introduction

The availability of the ECO start/stop function to stop the

engine is indicated to the driver by the ECO symbol in the
instrument cluster.

Display conditions *

Canada/USA
Driving: ECO ECO ECO
button button button

Start/stop function on and engine stop possible

Start/stop function on and engine stop not possible

(at least one stop inhibitor)

Start/stop function off OR start/stop function on and

fault
P54.33-4365-00

* The display concept differs in model variants of the USA national ver-
sion and does not apply for hybrid vehicles

Display conditions *

Canada/USA
Stop phase: ECO ECO ECO
button button button

Automatic engine stop active

Start/stop function on but at least one stop inhibitor

active, automatic engine stop not possible

Start/stop function on but operation preventing stop

(e.g. steering angle, N engaged or clutch not operated)
P54.33-4366-00

* The display concept differs in model variants of the USA national ver-
sion and does not apply for hybrid vehicles

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 ECO display concept

Introduction
On the launch of model series 205, a new symbol was in-
troduced in the instrument cluster display and on the ECO
start/stop function button.

P54.26-0156-00
Lower control panel
1 ECO start/stop function button

P54.33-4367-00

Instrument cluster in model series 205

1 ECO start/stop symbol

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 Function principle of ECO start/stop function
System description

The ECO start/stop function allows the engine to be shut off The ECO start/stop function allows the engine to be
at very low speeds and while stationary provided that certain switched off when the following conditions are met:
vehicle-dependent and driver-related conditions are met (au- General function requirements for the engine control ECO
tostop function). start/stop function:
• Circuit 15 (ignition ON)
In this way, fuel consumption is further reduced. If necessary, • Circuit 87M (engine control ON)
the starter can perform an automatic restart (autostart func- • Engine running
tion) of the engine. • Outside temperature in range: –10 °C < T < 40 °C
• System diagnosis completed and free of faults
While the engine is stopped, the electrical consumers are
supplied via the 12V starter battery. In vehicles with a backup Influenced by the driver:
concept, an additional battery supplies the on-board electri- • Doors are closed
cal system for the duration of the starting procedure. • Driver seat belt buckle is fastened
• After the key start, a speed of 8 km/h must have been
Certain criteria must be met for the ECO start/stop function exceeded
to be activated.
Manual transmission:
If the conditions are not satisfied, the ECO symbol in the • Speed is lower than 8 km/h
instrument cluster lights up yellow instead of green (on mo- • Accelerator pedal is not depressed
nochrome displays the ECO symbol disappears). The engine • Brakes are applied, or HOLD function is activated
is then not switched off when the vehicle is stationary. • Gearshift lever is at neutral and clutch is not operated

Automatic transmission:
• Vehicle stationary, speed is 0 km/h
• Brakes must be applied, or HOLD function activated
• Transmission mode D or N
• Accelerator pedal is not depressed
• Steering wheel must not be operated

bbNote
If the ECO indicator does not appear in the instrument
cluster and the green indicator lamp in the ECO button
does not light up, then either the system is switched
off or, in the rarest case, the ECO start/stop function
has actually been deactivated due to a fault!

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 Function principle of ECO start/stop function

System description
Vehicle-related parameters: Further parameters “temperatures and atmospheric
• Powertrain is open, transmission is in neutral pressures”:
• The driver is present (seat belt fastened and door contact • Coolant, gasoline engine: 60°C to 115°C
closed) • Coolant, diesel engine: 15°C to 115°C
• Engine hood is closed • Engine oil: 15°C to 130°C
• No crash has been detected • Outside temperature: -10°C to 40°C
• Component protection of the starter permits an auto- • Battery temperature: 0°C to 60°C (IBS)
matic stop • Diesel fuel temperature: 10°C to 90°C
• The fuel quantity is in the permissible range; the tank fill • Automatic transmission fluid: 10°C to 120°C
level is above reserve (diesel) • Gasoline engine: Ambient pressure below 0.75 bar or
• The speed threshold of 8 km/h has been exceeded once below 2500 m
(the speed threshold for the activation condition must • Diesel engine: Ambient pressure 0.7 bar or below 3000 m
have been exceeded once since the key start or after 3
automatic stops)
• The interior temperature set via the air conditioning sys-
tem has stabilized (the condition must only be met once
in the ignition cycle (circuit 15))
• Pressure reservoir of the brake system is sufficiently full
• Pressure reservoir of the air suspension (with AIRMATIC)
is sufficiently full
• Air suspension or ABC not in control intervention mode
• Steering wheel angle is < 210° (hydraulic power steering)
• Voltage of the on-board electrical system (batteries) is
sufficient, e.g. backup battery charge, intelligent battery
sensor (IBS), actual current too high, regeneration of die-
sel particulate filter (DPF), activation of rear window and
stationary heater

bbNote
After an automatic engine stop, a maximum of three
automatic engine starts without exceeding the speed
threshold of v = 8 km/h are permitted. After the
fourth engine start, the speed of v = 8 km/h must be
exceeded before the engine can be stopped again. If
the engine hood is opened during an automatic engine
stop, the ECO start/stop function is deactivated and
all the indicators in the instrument cluster light up. The
engine must then be restarted using the transmitter
key or via the KEYLESS-GO start/stop button (with
code 889 Keyless-Go).

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 Function principle of ECO start/stop function
System description

Driver/vehicle-related variable influencing the behavior of the ECO start/stop function

Stop enable sequence for the driver with manual Stop enable for the vehicle by:
transmission: • Stop enable by suspension and steering functions
• Vehicle moving • Stop enable by powertrain
• Brakes applied • Stop enable by climate control function
• Clutch operated • Stop enable by braking and control systems
• Transmission in neutral • Stop enable by on-board electrical system and energy
• Engine stops management
• Operate clutch
• Engine starts Prerequisites for the stop enable:
• Engage gear • After key start: v = 8 km/h exceeded
• Release clutch • After engaging “R”: v =15 km/h exceeded
• Release brakes, accelerate • After 4th stop when stationary: v =8 km/h exceeded
• Engine hood closed
Stop enable sequence for the driver with automatic • 3S engaged
transmission: • 3S not deactivated by system error
• Vehicle moving in “D” • Door closed and seat belt buckle fastened
• Apply brakes v = 0 km/h • No steering movement
• Engine stops
• Release brakes
• Engine starts
• Depress accelerator pedal
• Vehicle moving

P15.00-2273-00

Driver/vehicle-related variable influencing the behavior of the ECO start/stop function

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 Function principle of ECO start/stop function

System description
Function sequence for automatic engine start The ECO start/stop function performs an automatic start
In vehicles with manual transmission. the engine is started under the following conditions:
automatically when the accelerator pedal or the clutch pedal
is operated. With automatic transmissions, the engine is au- Driver-related conditions:
tomatically started when the brakes are released or the acce- • No gear is engaged (manual transmission)
lerator pedal is depressed. • The powertrain is open (automatic transmission)
• Engine hood is closed
The ME-SFI control unit actuates the starter circuit 50 re- • No crash has been detected
lay (K40/8kH, the designation may vary in different model • The driver is present (door contact closed and driver seat
series) with a ground signal. The power contact of the relay belt fastened)
closes and the solenoid switch of the starter (M1) is supplied
with voltage from “circuit 30” at “circuit 50”. Vehicle-related events:
• The maximum stop duration of 3 minutes is exceeded
Over the drivetrain CAN the fuel system control unit receives • The system detects fogging on the windshield
the CAN signal “Specified fuel pressure” from the ME-SFI • The brake system vacuum is below a threshold value
control unit and actuates the fuel pump (M3) accordingly. • The driver seat belt buckle is unfastened or the driver
door is opened
Function sequence for forced engine start (system- • The distance control system is active and requesting an
dependent start) engine start
The forced engine start subfunction is available as a protec- • Battery temperature < 0°C, > 60°C
tion function. This starts the engine automatically (with no • Coolant temperature (gasoline engine) < 60°C, > 110°C
action by the driver). • System or communication error in one of the following
systems: Driver seat occupancy, steering, on-board elec-
trical system, braking and control systems, accelerator
pedal, transmission, starter, engine

Driver-related control events:

• The clutch is operated and no gear is engaged
• The vehicle speed exceeds 2 km/h in forward travel and
immediately when rollback is detected (with automatic
transmission)
• The vehicle speed exceeds 8 km/h in forward travel and
reverse travel (with manual transmission)
• The accelerator pedal is operated
• The brake pedal is released or P mode is disengaged, or R
mode is engaged
• The steering wheel angle changes by more than 8° (HPS),
3° EPS without backup concept, 0° EPS with backup
concept
• A control intervention by the ABC or air suspension is
occurring
• User request for climate control system (defrost button)
• Operation of the ECO button to deactivate start/stop

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 Function principle of ECO start/stop function
System description

bbNote bbNote
When reverse gear is engaged, a maneuvering pro- Vehicles with electric steering do not have a maneu-
cess is detected and the ECO start/stop function is vering function because the steering operates even
deactivated. If the engine is in stop mode, a forced without engine assistance. A forced engine start is
engine start is performed by the system; if the engine performed if the steering is operated while the on-
is running, any engine stop is suppressed. The start/ board electrical system voltage is below the minimum
stop function is subsequently reactivated when a for- value.
ward gear is engaged and the vehicle speed exceeds
15 km/h. The engine is also started if the driver door
is opened, the driver's seat belt buckle is unfastened
or the ECO start/stop function is deactivated via the
ECO start/stop function button.

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 Function principle of ECO start/stop function

System description
Operation of ECO start/stop function with manual Sequence with manual transmission:
transmissions • Vehicle moving
In vehicles with manual transmission, the automatic stop • Speed v < 8 km/h
occurs with no further action by the driver when the • Brakes applied
speed v < 8 km/h and the transmission is in neutral and the • Clutch operated
clutch is not (no longer) operated and the brakes have been • Transmission in neutral
applied. • Release clutch
• Engine stops
• Operate clutch
• Engine starts
• Engage gear
• Depress accelerator pedal, release clutch
• Vehicle moves off

P15.00-2209-00
Illustration of function sequence with manual transmission

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 Function principle of ECO start/stop function
System description

Operation of ECO start/stop function with automatic Sequence with automatic transmission:
transmissions • Vehicle moving
In vehicles with automatic transmission, the automatic stop • Brakes applied
occurs with no further action by the driver as soon as the dri- • v = 0 km/h
ver comes to a standstill (stop = 0 km/h) in D mode with the • Standstill in “D”
brakes applied. • Engine stops
• Release brakes
• Engine starts
• Depress accelerator pedal
• Vehicle moves off

P15.00-2210-00
Illustration of function sequence with automatic transmission

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 Function groups 07 and 54

Function description
Refer to WIS for function descriptions of the ECO start/stop function
The description of the ECO start/stop function is divided into Information on the subfunction “energy management of the
in engine functions and electrical system functions. The sub- start/stop function” is included in the function description
function “engine control start/stop function” is considered “Energy management, function”.
from the perspective of the engine control system.

Function descriptions for engine control ECO start/stop in function group 07

P15.00-2267-00

Energy management of ECO start/stop in function group 54

P15.00-2268-00

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 Energy management of ECO start/stop function with additional battery
Function description

When the vehicle is stationary, the ECO start/stop function The relay check occurs after every key start and after every
automatically switches the engine off and restarts it as soon engine start from the stop function. If the relay check results
as the driver is ready to move off. in an error, a battery “red message” appears in the instru-
ment cluster.
Shutting off the engine when the vehicle is idle reduces fuel
consumption and thus the exhaust emissions. The master The on-board electrical system battery is decoupled from the
control unit of the ECO start/stop function is the CDI control on-board electrical system by the on-board electrical system
unit (N3/9) (with diesel engine) or the ME-SFI control unit decoupling relay (K19/7, or K1 in some model series) in ve-
(N3/10) (with gasoline engine), recording and evaluating all hicles with manual transmission and by the ECO start/stop
influencing factors. function diode (V19) in vehicles with automatic transmission.

It is still possible to switch off and start the engine conventi- The ECO start/stop function comprises the following
onally using the transmitter key (A8/1) or the KEYLESS-GO subfunctions:
start/stop button (S2/3) (in vehicles with code (889) Key- • Function sequence for engine stop
less-Go). The use of the ECO start/stop function additional • Function sequence for engine start
battery (G1/13) prevents any voltage dip which is noticeable • Function sequence for forced engine start
to the vehicle occupants when the engine is started (e.g. du- • Determining the status of the ECO start/stop function
ring radio or A/C operation). additional battery
• Charging the ECO start/stop function additional battery
The ECO start/stop function additional battery now assumes • Function description of voltage dip limiter (SEB)
the power supply for the active consumers while the 12V
starter battery (G1) is isolated from the on-board electrical
system (at engine start). Active comfort functions are not
switched off.

Immediately after the engine is cold-started, the CDI control

unit or the ME-SFI control unit performs a system diagnosis
and evaluates the operational capability of the start/stop
function.

The front SAM control unit with fuse and relay module
(N10/1) performs a so-called relay check of the components
involved in decoupling the 12V starter battery and connec-
ting the ECO start/stop function additional battery. The pre-
requisite for this check is a vehicle speed > = 20 km/h once
since engine start.

bbNote
The ECO start/stop function additional battery is
connected by closing the ECO start/stop function
additional battery relay (K114 electrical relay, K57/2
mechanical relay).

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 Function sequence for engine stop

Function description
As the master control unit for the ECO start/stop function, In model series 172, W/X204, 207, 212, 218 and 231, the
the CDI control unit or the ME-SFI control unit checks the va- following information for the on-board electrical system ma-
rious influencing factors for the stop enable signal. nagement is provided by the rear SAM control unit with fuse
and relay module (N10/2):
For this, the on-board electrical system management supplies • State of the on-board electrical system battery
information which describes the state of, and the demands • State of the ECO start/stop function additional battery
on, the on-board electrical system. • State of the on-board electrical system
• Requirements of load-intensive consumers (e.g. air
conditioning)
The CDI control unit or the ME-SFI control unit evaluates all
relevant data and then issues the stop enable signal accor-
dingly. The engine is then switched off.

bbNote bbNote
In model series 117, X156, 176, 246 and W/X 166, When the blower for automatic air conditioning is ac-
the function is contained in the SAM (N10), and in mo- tive, the blower output is reduced. At warm ambient
del series 222 in the front SAM (N10/6) temperatures, the system switches to air recirculation
mode depending on the specified temperature setting.

After an engine stop, a maximum of three engine

starts without exceeding the speed threshold of
v = 8 km/h are permitted.

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 Function sequence for engine start
Function description

The CDI control unit or the ME-SFI control unit evaluates all The on-board electrical system battery provides the energy
of the relevant variables and issues the start enable signal required to start the engine.
(warm start signal).
As soon as the CDI control unit or the ME-SFI control unit
The front SAM control unit (N10/6, N10 in model series 117, detects an engine speed of n = 400 to 700 rpm, it terminates
X156, 176, 246 and W/X 166) reads this warm start signal the starting procedure and transmits a corresponding signal
over a direct line and actuates the on-board electrical system over the chassis CAN 1 (CAN E1) to the front SAM control
decoupling relay (manual transmission) or the ECO start/ unit. The front SAM control unit then actuates the on-board
stop function diode (automatic transmission) in the front pre- electrical system decoupling relay (manual transmission) or
fuse box (F32, in model series 222 F33) and the ECO start/ the ECO start/stop function diode (automatic transmission)
stop function additional battery relay. and the ECO start/stop function additional battery relay.

The ECO start/stop function additional battery is connected The on-board electrical system decoupling relay (manual
to the on-board electrical system. Shortly afterwards, the transmission) or the ECO start/stop function diode (auto-
on-board electrical system decoupling relay (manual trans- matic transmission) connects the 12V starter battery to the
mission) or the ECO start/stop function diode (automatic on-board electrical system. The ECO start/stop function
transmission) disconnects the on-board electrical system additional battery relay isolates the ECO start/stop function
battery from the on-board electrical system for the duration additional battery from the on-board electrical system. The
of the starting procedure. power requirements of the on-board electrical system are
once again provided by the 12V starter battery.
The power requirements of the on-board electrical system
are now provided by the ECO start/stop function additional
battery. This prevents any voltage dip which would otherwise
be noticeable to the vehicle occupants when the engine is
started (e.g. during radio or A/C operation).

bbNote
In model series 212 as of 03/13, a prefuse box with
V19 (diode) is installed! Also in vehicles with manual
transmission.

The wiring diagram for this can be found in WIS under:

PE54.15-Q-2502-97DAA

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 Function sequence for forced engine start

Function description
In order to ensure the stability of the on-board electrical sys- When the on-board electrical system management can no
tem even with the engine stopped, the CDI control unit or the longer guarantee the stability of the on-board electrical
ME-SFI control unit can initiate a forced engine start. system, the rear SAM control unit transmits an engine start
request over the interior CAN (CAN B), the front SAM control
A forced engine start is carried out if the stability of the on- unit and chassis CAN 1 to the CDI control unit or the ME-SFI
board electrical system can no longer be guaranteed due to control unit.
the requirements of load-intensive consumers. Load-intensive
consumers may be requested by the following systems: The CDI control unit or the ME-SFI control unit receives this
• Supplemental restraint system and starts the engine. If the stability of the on-board electri-
• PRESAFE cal system still cannot be guaranteed after this, the engine
• Brake Assist System and distance control systems is not switched off again. The ECO start/stop function is
• Air conditioning deactivated.
• Steering
• Shifting from P to D or from N to D (depending on model
series)

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 Illustrations of the power supply principle
Function description

P15.00-2213-00

B95 Intelligent battery sensor (IBS) M1 Starter

G1 On-board electrical system battery N10/1 Front SAM control unit with fuse and relay module
G2 Alternator (except model 212.095) N10/2 Rear SAM control unit with fuse and relay module
G1/13 ECO start/stop function additional battery V19 ECO start/stop function diode (diode open)
K19/7 On-board electrical system decoupling relay (relay open) A With manual transmission
K114 ECO start/stop function additional battery relay (relay closed) B With automatic transmission

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 Illustrations of the power supply principle

Function description
P15.00-2214-00
B95 Intelligent battery sensor (IBS) M1 Starter
G1 On-board electrical system battery N10/1 Front SAM control unit with fuse and relay module
G2 Alternator (except model 212.095) N10/2 Rear SAM control unit with fuse and relay module
G1/13 ECO start/stop function additional battery V19 ECO start/stop function diode (diode open)
K19/7 On-board electrical system decoupling relay (relay open) A With manual transmission
K114 ECO start/stop function additional battery relay (relay closed) B With automatic transmission

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 State of ECO start/stop function additional battery
Function description

Immediately after the engine is started, the front SAM cont- The ECO start/stop function additional battery relay is no
rol unit carries out the process of battery state recognition, longer actuated under the following conditions:
and the so-called relay check of the components involved • ECO start/stop function additional battery
in decoupling the on-board electrical system battery and deep-discharged
connecting the ECO start/stop function additional battery • Internal short circuit
(described under “Function sequence for engine stop”). • Short circuit in positive line of ECO start/stop function
additional battery
The check supplies information about the availability of • Malfunction of additional battery coupling relay (relay fails
electrical power from the ECO start/stop function additional to close (K57/2 and K114 relay opens due to an internal
battery. fault (K114))

If the engine is switched off during the battery state recogni- To ascertain this, the voltage of the ECO start/stop func-
tion process, the front SAM control unit aborts it and rejects tion additional battery is compared with an internal value. A
the results up to that point. corresponding fault message is shown in the multifunction
display (A1p13) of the instrument cluster (A1).
In addition to battery state recognition, the voltage at the
ECO start/stop function additional battery is tested after The data required for this is transmitted by the SAM control
every engine start in start/stop function mode. unit (in model series 172, W/X204, 207, 212, 218, 231, rear
SAM (N10/2), model series 117, X156, 176, 246 and W/X
Battery state recognition can also be launched using the dia- 166, SAM (N10), in model series 222, front SAM (N10/6))
gnostic tester. over the interior CAN to the instrument cluster.

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 Charging the ECO start/stop function additional battery

Function description
The charging strategy of the ECO start/stop function additio- If the voltage dip (U < 11 V) at engine start is too great, the
nal battery must take two requirements into account: engine stop function is deactivated for t = 1 minute in order
• A sufficient charge level must be maintained in the ECO to recharge the ECO start/stop function additional battery.
start/stop function additional battery.
• The number of actuations of the ECO start/stop function The ECO start/stop function additional battery is only
additional battery relay and the associated load on the connected if the output limitation of the alternator is not
ECO start/stop function additional battery must be mini- active and the on-board electrical system voltage is high
mized as far as possible. enough (U > 13 V). It is disconnected again if the output li-
mitation of the alternator is active or if the on-board electrical
If the open circuit voltage (U > 12.5 V) of the ECO start/stop system is severely overloaded.
function additional battery is too low, the alternator's output
limitation (alternator management) (except model 212.095)
is deactivated so that the ECO start/stop function additional
battery can be charged.

bbNote
In vehicles of model series 117, X156, 176, 246 and
W/X 166, the ECO start/stop function additional
battery is charged at 200 mA when the engine hood is
open and the SAM (N10) detects that it is being char-
ged from an external source.

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 Other components and functions
Function description

Function description of voltage dip limiter (SEB) without additional battery

Model series 205 is the first model in which the additional When the engine is being started, a voltage is applied to
battery has been replaced with a voltage dip limiter. the voltage dip limiter. From this it detects the starting pro-
cedure and connects the series resistor. If the on-board
The use of the voltage dip limiter (R62) at the positive ter- electrical system voltage drops too much due to the high
minal of the on-board electrical system battery reduces any power consumption of the starter, the voltage dip limiter
voltage dip which is noticeable to the vehicle occupants when disconnects the series resistor again. It should be noted that
the engine is started (e.g. during radio or A/C operation). 12 V is only present at the starter positive line during the
starting procedure.
The voltage dip limiter is an electronically switchable series
resistor which for reducing the high power consumption of
the starter (M1) when it is starting to crank the engine and
is connected via circuit 87 to the starter circuit 50 relay
(K40/8kH).

P15.30-2290-00
Voltage dip limiter (R62)

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 Other components and functions

Function description
P15.30-2296-00

Wiring diagram of voltage dip limiter

1 Circuit 30 consumer RSS No-load current shutoff relay
2 Circuit 30g consumer S Starter
G Alternator SEB Voltage dip limiter
IBS Intelligent battery sensor

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 Other components and functions
Function description

Function description of starter front-end relay (SVR)

Model series 117, 156, 176, 242 and 246 as of 03.11.2014 When the engine is started by the CDI control unit, the ME-
without code 460 (Canada version) have no additional bat- SFI control unit or the powertrain control unit, a voltage is
tery; a starter front-end relay (SVR) (K92) is used instead. In applied to the starter front-end relay. From this it detects the
model series 205 with engine 274, the starter front-end relay starting procedure and connects the resistor. If the on-board
is used from 2015 onwards. electrical system voltage drops too much due to the high
power consumption of the starter, the starter front-end relay
The starter front-end relay (K92) has no semiconductor out- disconnects the resistor again.
put stages, but two mechanical relays. It connects and dis-
connects a fixed resistance for a certain period of time (120
msec). This reduces the high power consumption of the star-
ter (M1) when it is starting to crank the engine. The starter
front-end relay (K92) is connected via circuit 87 to the starter
circuit 50 relay (F58kM).

P15.30-2292-00
Starter front-end relay (K92)

bbNote
The wiring diagram for model series 117, 156, 176,
242 and 246 as of 03.11.2014 without code 460
(Canada version) can be found in WIS under:
P15.00-Q-2101-97IAA

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 Other components and functions

Function description
Brief description of direct starting function for gasoline Auxiliary oil pump (ZÖP)
engines When the engine is shut off in start/stop mode, the auxiliary
Gasoline engines are equipped with a starter-assisted in-en- oil pump takes over the task of supplying oil to the hydraulic
gine direct starting function. This function together with the controller unit of the transmission from the primary pump
engine stop function constitutes a direct starting function which is now idle, in order to enable the vehicle to move off
which makes use of the fact that, with the selected piezo quickly and smoothly when the engine is restarted.
injection valve coupled with the correct injection timing, the
very first compression stroke of a cylinder can be utilized for The auxiliary oil pump is a powertrain CAN bus subscriber.
a controlled combustion. Fault codes are stored in the transmission control unit. It is
an independent component with its own control unit.
Clutch protection (as of model series 205)
The clutch protection function calculates the temperature of There are a variety of conditions (stop inhibitors, start re-
the clutch constantly. At 300 °C a red message is activated questers) which must be fulfilled for the ECO start/stop
in the display together with a warning tone. In parallel with system to be activated. If the engine does not shut off or
this display, a stop inhibitor event is set because the clutch restarts against the expectations of the customer, this does
cools down more quickly when the engine is running due not necessarily mean that there is a fault.
to the turbulence of the air. The red message disappears at
250 °C and the stop inhibitor is revoked.

P54.33-4752-00 P27.57-2054-00
Automatic transmission with auxiliary oil pump
Clutch protection display

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 Other components and functions
Function description

Deactivation of the ECO start/stop function in model Standard logic of the climate control with ECO start/stop
series 205 function (model series 212, 204, 205, 172, 176, 246)
In model series 205 equipped with “Agility Select”, the ECO The air conditioning blocks the ECO start/stop enable signal
start/stop function is deactivated in the “Sport Plus” trans- after ignition ON until the interior target value is almost rea-
mission mode. The ECO start/stop function can be reactiva- ched. Subsequently, the ECO start/stop enable signal is not
ted using the ECO start/stop button! revoked again, with the exception of a fogging situation, in
which the ECO indicator remains permanently green.

bbNote The blower reduction at engine stop has a factor of 0.8. At

If the ignition remains off for more than four hours, outside temperatures of approx. 25°C and above, the climate
then the next time the engine is started, the trans- control is assisted by 100% recirculated air when the engine
mission mode “C” is engaged and the ECO start/stop is stopped.
function is active again.
Climate control logic with ECO start/stop (model series
222, 231,166)
A/C operation with ECO start/stop function The air conditioning blocks the ECO start/stop enable sig-
Due to its networking with the climate control system, the nal after ignition ON until the interior target value is almost
ECO start/stop function is automatically deferred when the reached.
interior temperature drops below the set value. The air con-
ditioning prevents the engine from being stopped until the Subsequently the ECO start/stop enable signal is revoked
preselected interior temperature is reached. If the interior when the engine is stopped if:
temperature increases above the preselected value during • The evaporator temperature rises (threshold 17°C coded)
subsequent stops, the air conditioning does not request a • The minimum stop duration has elapsed (40 s coded)
forced engine start in order to save energy and the refrige- • Fogging situation
rant compressor is not activated (unless there is a risk of the
windows fogging up). This can result in a reduced cooling Engine starts. Stop is disabled until the vehicle has stabilized
output while the engine is stopped if the outside temperature again. At outside temperatures of approx. 25°C and above,
is high. the climate control is assisted by 100% recirculated air when
the engine is stopped.
If this is not desired, the ECO start/stop function must be
deactivated by pressing the ECO start/stop function “ECO
Off” button.

P54.26-0157-00
Agility Select selector lever

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 Stop prohibitions and stop inhibitors

Stop prohibitions and stop inhibitors

P15.00-2272-00

Display concept

Description Description
• System state of the vehicle which necessitates a • System state which results in a temporary or perma-
temporary stop prohibition. nent shutdown of the system.

Examples of stop inhibitors are: Examples of system errors are:

• Outside temperature too low • A breakdown in communication with a relevant
• On-board electrical system voltage too low system
• A defect in the electrical system switchover

Stop inhibitor Stop prohibition

System state of the vehicle which temporarily inhibits the System state of the vehicle in which a fault relevant to the
automatic shutoff of the engine: No ECO indicator (mo- ECO start/stop function is found in a control unit involved in
nochrome IC display) or yellow ECO indicator (color IC the function, and an engine stop is prohibited.
display).
This results in the deactivation of the ECO start/stop func-
If the engine is not switched off automatically despite correct tion for the entire driving cycle. The ECO indicator is not vi-
operation, this does not necessarily mean that there is a sible in the instrument cluster and the LED in the ECO button
fault. There are system-related demands which require the is off.
engine to be running and therefore necessitate a stop inhibit.

For example, the engine is not switched off when the hood
or the driver door are open or the seat belt buckle is not
fastened.

A functioning on-board electrical system has priority over the

stop function. The engine is not switched off, for example,
when a large number of consumers are active so that any
subsequent undervoltage and consumer shutoff can be indi-
cated to the driver. A stop inhibitor in the on-board electrical
system is not automatically a fault.

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 Stop prohibition system analysis
Diagnosis in Xentry Diagnostics

Diagnosis of the ECO start/stop function is always per-

formed from the Function/ECO start/stop function home
screen.

The checklist (OF15.40-P-3000-01A) should be used to assist

with diagnosis.

The system analysis is basically divided into the analysis of

stop prohibitions and stop inhibitors.
P15.00-2274-00
ECO start/stop function home screen

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 Stop prohibition system analysis

Diagnosis in Xentry Diagnostics

Switch on ignition

Start engine and wait 30s

ECO LED
off

Output: Fault status of ECO

start/stop function

Read out current fault status

P15.00-2253-00

Read out fault memory of

yes no Read out stored fault
affected control unit and Fault present?
process fault codes status

Read out fault memory of

affected control unit and
process fault codes
yes
Fault present?
no

No stop prohibition present.

Continue with stop inhibitor Output: Fault status of
system analysis ECO start/stop function
(stored)

P15.00-2254-00

bbNote bbNote
The fault status of the ECO start/stop function indica- The fault status of the ECO start/stop function indica-
tes the current fault status of the individual systems. tes the most recently occurring fault in the individual
If one of the values here is set to “NOT OK”, the fault systems. First, the kilometer reading must be checked
codes of the affected control unit must be read out. to verify that the fault matches the current problem.
Any faults present must be processed. If one of the values here is set to “NOT OK”, the fault
codes of the affected control unit must be read out.
Any faults present must be processed.

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 Stop inhibitor system analysis
Diagnosis in Xentry Diagnostics

If a stop inhibitor occurs, the circular buffer must first be read

out under “Engine stop inhibit”. This gives an initial indication
of the system causing the problem.

Switch on ignition

Start engine and wait 30s

ECO LED
yellow

Output: Circular buffer

History of stop inhibitors
over the last engine runs
Read out circular
buffer
P15.00-2255-00

Identify faulty
components

Cause in electrical system Cause in A/C, engine or electrical sys-

• Read out electrical system tem. Read out stop inhibitors via actual
• Perform a test drive values of relevant system
• Observe stop inhibitor • Identify affected system
• Identify affected system • Evaluate actual values of affected
control unit

bbNote
If the on-board electrical system is identified in the
circular buffer as the primary cause of the stop inhibit,
continue troubleshooting under “Engine stop inhibit/
on-board electrical system”. There, an exact analysis
must be performed of the reasons for a problem in the
on-board electrical system.

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 Stop inhibitor system analysis (manual selector) (ECO start/stop indicator green)

Diagnosis in Xentry Diagnostics

An inoperative ECO start/stop function, despite a green indi-
cator, in vehicles with manual transmissions should be analy-
zed as described below.

Switch on ignition

Start engine and wait 30s

ECO LED
green

Output: Prerequisite for

Perform a test drive and ob- automatic engine stop

serve stop inhibits

P15.00-2256-00

Identify faulty components

Observe actual value of components

bbNote
This is the only way to diagnose a fault in the clutch
switch, for example.

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 System analysis in Xentry Diagnostics, overview
Diagnosis in Xentry Diagnostics

Switch on ignition

Output: “Circular buffer”

Read out circular buffer History of stop inhibitors
over the last five engine runs

Start engine and wait 30s

no Read out fault status informa-

ECO LED Output: “Fault status of ECO
on? tion from ECU via diagnosis start/stop function”

yes

Output: “Fault status of

Read out last stored fault
ECO start/stop function
(stored)”

Drive and observe stop inhibi-

Output: “Causes for engine
tors with Xentry Diagnostics
stop inhibit”

Drive and perform extended Output: “Engine stop inhibit

diagnosis component”+“Components”

bbNote bbNote
The diagnosis steps shown indicate the maximum The diagnosis scope available in Xentry for the ECO
scope at the copy deadline start/stop function varies for different model series
and variants.

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 System analysis in Xentry Diagnostics, overview

Diagnosis in Xentry Diagnostics

There is a fault in the system only if:
• There is an entry in the fault status of the ECO start/stop bbNote
function The circular buffer can give only an initial indication of
• A system error in the entire driving cycle is entered as a the affected system. For a more accurate analysis of
stop inhibitor the cause, a test drive must be performed.

For an initial analysis the circular buffer of the start/stop fun-

ction should be read out.

bbNote
For a supporting analysis of the ECO start/stop fun-
ction, the diagnosis tree for the ECO start/stop func-
tion can be used.

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 Read out circular buffer
Diagnosis in Xentry Diagnostics

Switch on ignition

Output: “Circular buf-

Read out circular fer” History of stop
buffer inhibitors over the last
five engine runs

Circular buffer If a stop inhibitor does not occur in a driving cycle, then no
The circular buffer stores the stop inhibitors from the last five entry is made in the circular buffer. This means that, for ex-
driving cycles. ample, between driving cycle 1 and driving cycle 2 in the cir-
cular buffer there may have been several other driving cycles
It saves the first seven stop inhibitors of each driving cycle. in which a stop inhibitor did not occur.
(Exception CRD3: Here, the first 15 stop inhibitors for each of
the last three driving cycles are stored). “Driving cycle 1” is always the last driving cycle performed
in which a stop inhibitor occurred.
The circular buffer does not begin to record within a driving
cycle until the basic vehicle-related requirements for the The values of the current driving cycle can only be read out
ECO start/stop function are satisfied (e.g. 18 km/h speed when the driving cycle has ended! This requires an ignition
threshold exceeded). cycle with engine run-on.

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 Read out circular buffer

Diagnosis in Xentry Diagnostics

P15.00-2266-00

1 A driving cycle commences at engine start and ends after ignition off. Driving 3 Time in minutes after the commencement of the driving cycle at which the
cycle 1 is always the last driving cycle performed in which a stop inhibitor stop inhibitor occurred.
occurred. 4 The stop inhibitors are marked with a cross.
2 The counter shows the sequential number of the stop inhibitor in this driving 5 Time after the commencement of the driving cycle at which the first success-
cycle. Between two stop inhibitors there may be one or more successful en- ful engine stop was performed. If there were no engine stops in the entire
gine stops. These are not identifiable. driving cycle, the value is set to “255 min”!

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 Read out fault status of ECO start/stop function
Diagnosis in Xentry Diagnostics

Switch on ignition Read out circular buffer Start engine and wait 30s

Output: “Fault status of ECO Read out fault status informa- ECO LED
start/stop function” tion from ECU via diagnosis on?

P15.00-2253-00

The fault status of the ECO start/stop function indicates the

current fault status of the individual systems. If one of the
values here is set to “NOT OK”, the fault codes of the affec-
ted control unit must be read out. Any faults present must be
processed.

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 Fault status of ECO start/stop function (STORED)

Diagnosis in Xentry Diagnostics

Switch on ignition Read out circular buffer Start engine and wait 30s

Output: “Fault status of yes ECO LED

ECO start/stop function Read out last stored fault
on?
(stored)”

P15.00-2254-00

The fault status of the ECO start/stop function indicates the

most recently occurring fault in the individual systems. First,
the kilometer reading must be checked to verify that the fault
matches the current problem. If one of the values here is set
to “NOT OK”, the fault codes of the affected control unit are
read out. Any faults present must be processed.

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 Read out causes for engine stop inhibit
Diagnosis in Xentry Diagnostics

Switch on ignition Read out circular buffer Start engine and wait 30s

yes
Drive and observe stop inhibi- ECO LED
Read out last stored fault
tors with Xentry Diagnostics on?

Output: “Causes for engine

stop inhibit”

P15.00-2256-00

The current stop inhibitors in the driving cycle can be identi-

fied under “Causes for engine stop inhibit”. This view is active bbNote
only during a test drive. If either the engine or the air conditioning system
is identified under “Causes for engine stop inhibit”,
continue to a more accurate diagnosis under “Engine
stop inhibit (components)”. For all other components
the actual values of the component in question can be
analyzed under “Components”.

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 Requirements for automatic engine start

Diagnosis in Xentry Diagnostics

Switch on ignition Read out circular buffer Start engine and wait 30s

Drive and observe stop inhibitors yes ECO LED

Read out last stored fault
with Xentry Diagnostics on?

Output: “Engine stop

Drive and perform extended
inhibit component”+
diagnosis
“Components”

The requirements for the automatic engine start are only Otherwise these values indicate the same as the “Causes for
used in the event of problems related to an implausible engine stop inhibit”.
engine start while the engine is at automatic engine stop.

P15.00-2257-00

Extended diagnosis via “Engine stop inhibit

(components)” and “Components” bbNote
If the engine, the air conditioning or the on-board elec-
trical system is identified under “Causes for engine
stop inhibit”, continue to a more accurate diagnosis
under “Engine stop inhibit (components)”. For all other
components the actual values of the component in
question can be analyzed under “Components”.

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 Engine stop inhibit (components)
Diagnosis in Xentry Diagnostics

Read out causes for engine stop inhibit (combustion engine)

P15.00-2258-00

“Causes for engine stop inhibit (combustion engine)” lists the nent is identified here, the diagnosis can be continued under
individual potential causes related to the engine. If a compo- “Components”.

Requirements for automatic engine start (combustion engine)

P15.00-2259-00
The requirements for the automatic engine start (combustion
engine) contain information when the engine restarts prema-
turely after an automatic engine stop.

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 Engine stop inhibit (components)

Diagnosis in Xentry Diagnostics

Read out causes for engine stop inhibit (air conditioning)

P15.00-2260-00

“Engine stop inhibit (air conditioning)” lists the individual stop

inhibitors within the air conditioning system.

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 Diagnosis of ECO start/stop function via actual values of electrical system data
Diagnosis in Xentry Diagnostics

P15.00-2261-00
Diagnosis via the on-board electrical system data is to be
performed when the circular buffer lists the on-board electri-
cal system as the cause of the stop inhibit.

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 Diagnosis of ECO start/stop function via actual values of electrical system data

Diagnosis in Xentry Diagnostics

OK driving cycle with ECO start/stop function available and active

P15.00-2264-00

1 Alternator management active after a short time. Normal state! 4 Battery state of charge (SOC) normal (~80%)
2 ECO start/stop function is available for the entire driving time. 5 Positive charge balance
3 Automatic engine stop active for approx. 2 min, e.g. at traffic lights

Driving cycle with many consumers active, ECO start/stop function is intermittently unavailable

P15.00-2263-00

1 Alternator management active after a short time 4 Battery charge at engine start very good (91%)
2 ECO start/stop function is not available for the entire driving time 5 Negative charge balance
3 Automatic engine stop active for approx. 20 min

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 Diagnosis of ECO start/stop function via actual values of electrical system data
Diagnosis in Xentry Diagnostics

OK driving cycle with ECO start/stop function available and active

P15.00-2262-00

1 ECO start/stop function is available for only a short time. 3 Low outside temperature at engine start
2 Battery charge at engine start good (~80%) 4 Slightly positive charge balance

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 Read out actual values of “Components”

Diagnosis in Xentry Diagnostics

“Components” lists the actual value groups of the various
components. The current status for each component is
shown. This can be an indication of the ultimate cause of the
stop inhibit.

Combustion engine

P15.00-2247-00

Supplemental restraint system

<BILD-ID
P15.00-2248-00

Brake system

P15.00-2249-00

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 Read out actual values of “Components”
Diagnosis in Xentry Diagnostics

Air conditioning

P15.00-2250-00

On-board electrical system

P15.00-2251-00

Engine hood

P15.00-2252-00

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 ECO start/stop function diagnosis tree

Diagnosis in Xentry Diagnostics

P15.00-2271-00

Diagnosis tree

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 Notes/fault profiles
Notes/fault profiles

Known fault profiles and information on the diagnosis and repair of the ECO start/stop function are listed below.

Group 07: Group 14:

• The engine control unit performs a diagnostic routine • In vehicles with engine 607 the regeneration process
shortly after engine start. Various functions, such as the of the diesel particulate filter constitutes an additional
self-adjustment function, are checked internally. For this stop inhibitor. When regeneration processes are aborted
function to complete, it is necessary for the engine to prematurely, the stop function is not available. The ECO
operate at idle for approx. 45 seconds with the vehicle start/stop function does not operate again until the rege-
stationary. The diagnostic routine is then completed and neration process has been completed successfully.
the stop function is activated. If the vehicle is driven on • The ECO start/stop function is not enabled if the load
the freeway, for example, immediately after engine start, state of the diesel particulate filter is > 150%.
the stop with 45 s idling does not occur. Because of
this, the stop function can remain inactive over a longer
period of time. The diagnostic routine is reactivated in
the engine control unit at every ignition sequence. If an
ignition sequence is interrupted manually with the key,
the process will be repeated in the next driving cycle. A
special case exists in vehicles with engine 271 (EVO). The
stop function is initially activated immediately after engine
start. After a short time, the stop function is suppressed
again as the diagnostic routine commences. When the di-
agnostic routine has finished, the stop function is reacti-
vated after approx. 45 seconds with the vehicle stationary
and idling.

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 Notes/fault profiles

Notes/fault profiles
Known fault profiles and information on the diagnosis and repair of the ECO start/stop function are listed below.

Group 25:
• In vehicles with manual transmission, damage to the elec-
trical feed lines of the clutch pedal switch or incorrect
fastening of the switch can interfere with the ECO start/
stop function.
• In model 246 with manual transmission, damage to the
ground cable on the upper clutch switch (S40/3) can
shut down the ECO start/stop function. No faults are sto-
red. The green LED in the ECO button lights up; the ECO
symbol in the instrument cluster is displayed. Repair the
damage in accordance with repair method AR00.19-P-
0100A using a solder connector AR00.19-P-0100-09A.

P25.20-2072-00 P25.20-2073-00
Damage to the ground cable on the upper clutch switch Damage to the electrical feed lines of the clutch pedal switch

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 Notes/fault profiles
Notes/fault profiles

Group 27: References to published TIPS documents

• The ECO start/stop function is inoperative following
replacement of the auxiliary oil pump. The ECO start/ Group 15.30:
stop function has a fault. The cause could be the auto- • ECO start/stop, no stop function possible (stop inhibi-
matic transmission. The following fault is logged in the tors), fault codes (FC) 90B2 and 90B9
transmission control: U113800 -  Communication with • ECO start/stop function intermittently inoperative
the electric oil pump control unit at the transmission has
a malfunction. Remedy: Check whether the wrong auxili- Group 54.10:
ary oil pump was installed and exchange it for the correct • ECO start/stop function intermittently inoperative
component if necessary. • Engine start/stop inoperative or engine starts up at ran-
dom or 12 V on-board electrical system voltage too low
Group 54: • Vehicle does not perform automatic engine stop
• In vehicles without additional battery, voltage fluctuations • Start/stop function, engine does not stop
can cause slight flickering in halogen lamps (primarily the • Start/stop intermittently inoperative - Stop inhibitor in
brake lights). This applies only for vehicle models which on-board electrical system
previously had an additional battery installed.
• In vehicles without additional battery, the steering can Group 54.18:
stiffen when the engine stops. (Not in the A-Class, • ECO start/stop inoperative, gearshift recommendation
B-Class, GLA and CLA; these models are less sensitive to inoperative
voltage dips). No faults are logged. The engine restarts
when the steering is turned.
• In models 166, 176 and 246, the ECO start/stop function
is suppressed until the battery capacity (SOC) is >80%. It
is then recharged for a further 15 minutes. Only then is
the stop function reactivated! At ignition OFF/ ON, the
recharge time is interrupted and the stop function is acti-
vated directly at >80%. The recharge time can be shorte-
ned by new SCN coding of the rear SAM.
• The battery tests should be performed using the MIDT-
RONICS tester in Taxi mode! The internal resistance of
the battery must be checked. If the battery still has a high
current drain after charging for a long time, then it may
have to be replaced.
• The battery sensor must be checked using the Xentry Dia-
gnostics system as described in TIPS.
• Important for vehicles in stock! Battery care procedures
stipulate charging via the jump-start connection point
every 6 weeks.

Group 83:
• If there are permanent stop inhibitors in the air conditi-
oning system and the actual values are OK, the codings
for the A/C system must be checked (characteristic for
hot countries, YES/ NO, evaporator temperature limit for
automatic engine stop, A/C operating mode during auto-
matic engine stops, COMFORT or STANDARD).

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 Checklist for ECO start/stop function

Notes/fault profiles
Questions for fault rectification Tick as appropriate and comment if necessary

Is the green LED in the ECO button constantly lit? ⎕ Yes

⎕ No

If no:
⎕ Was the ECO button pressed beforehand?
⎕ Was it possible to switch the LED back on with the ECO button?

Was the ECO symbol in the instrument cluster vi- ⎕ Yes: There are no stop inhibitors.
sible? (Monochrome display) ⎕ No: There is a stop inhibitor.

Was the ECO symbol in the instrument cluster vi- ⎕ Yes

sible? (Color display) ⎕ Green: There are no stop inhibitors.
⎕ Yellow: There is a stop inhibitor.
⎕ No: System is switched off or there is a fault in the start/stop
function.

Was the ECO symbol in the instrument cluster -

continuously not visible or yellow? Yes ⎕ No ⎕
not visible or yellow multiple times? Yes ⎕ No ⎕
not visible or yellow for a short time? Yes ⎕ No ⎕
not visible or yellow once for a long time? Yes ⎕ No ⎕
not visible or yellow multiple long times? Yes ⎕ No ⎕

Have all the required operator events for the auto-

matic stop been performed?

Manual transmission: Selector lever at “N”, clutch pedal not operated, brake pedal depres-
sed sufficiently hard and V < 8 km/h
Fulfilled ☐ Not fulfilled ☐

Automatic transmission: Selector lever at “D” or “N”, brake pedal depressed sufficiently hard,
accelerator pedal not operated and V = 0 km/h
Fulfilled ☐ Not fulfilled ☐

Other:
Driver seat belt fastened? Yes ☐ No ☐
Driver door closed? Yes ☐ No ☐
Engine hood closed? Yes ☐ No ☐

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 Abbreviations
Annex

CRD3 OBF
Engine OM651 with engine control unit CDID3 Upper control panel (UCP)

DPF ME
Diesel particulate filter Gasoline engine control unit

ECO MOPF
Engine cut off Facelift

EPS MSG
Electronic power steering Engine control unit (ECU)

HPS SEB
Hydraulic power steering Voltage dip limiter

IBS SG
Intelligent battery sensor Control unit (CU)

KI SAM
Instrument cluster (IC) Signal acquisition and actuation module

KLA SOC
Automatic air conditioning (AAC) State of charge

LED ZÖP
Light-emitting diode Auxiliary oil pump

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 Index

Annex
A V
Shut-off of ECO start/stop function (Agility Select, Sport Prefuse box with diode (V19) p. 19
plus) p. 26 X
Abbreviations p. 50 Xentry p. 28 ‐ 45
Analysis and diagnosis with Xentry p. 28 – 45 Z
Display concept of ECO start/stop function p. 7 – 8 Additional battery p. 22 ‐ 23
Auxiliary oil pump (ZÖP) p. 25
B
Component overview (model series 205) p. 4 – 5
On-board electrical system data (Xentry) p. 41 – 43
C
Checklist for ECO start/stop function p. 49
D
Diagnosis tree p. 46
Direct start function p. 25
F
Function principle of ECO start/stop function p. 9 – 15
E
ECO start/stop in WIS p. 16
Energy management of ECO start/stop function with
additional battery p.17
F
Fault profiles &amp; information on diagnosis &amp; repair
(Xentry) p. 48 ‐ 48
Fault status (Xentry) p. 35 ‐36
Function sequence for engine stop p. 18
Function sequence for engine start p. 19
Function sequence for forced engine start p. 20
K
Climate control with ECO start/stop function p. 26
Reading component actual values for ECO start/stop
function (Xentry) p. 43 ‐ 45
Clutch protection p. 25
R
Circular buffer (Xentry) p. 34
S
Circuit diagram of power supply, engine start p. 21
Circuit diagram of power supply, engine running p. 21
Voltage dip limiter (SEB) p. 24
Starter front-end relay (SVR) p. 25
Stop prohibition p. 27
Stop inhibitors p. 27
Stop inhibitors (Xentry) p. 28 ‐ 29
Stop prohibition (Xentry) p. 30 ‐ 31
System analyses (Xentry) p. 32 – 33

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 Information and copyright
Annex

Product portfolio
You can also find comprehensive information on our com-
plete product portfolio in our Internet portal:
Link: http://aftersales.mercedes-benz.com

Questions and suggestions

If you have any questions or suggestions concerning this pro-
duct, please write to us.
E-mail: customer.support@daimler.com

© 2015 by Daimler AG
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