Intelligent Technology181
Using the systemSafetyDriving TipsGeneral MaintenanceBreakdown assistanceTechnical Data
Driving Tips
Intelligent Technology
Electronic stability programme (ESP)*
General
General
The ESP aids you maintain control of your vehicle in situations in borderline driving
situations such as when negotiating a curve too fast. The risk of skidding is reduced
and your car thus offers greater driving stability depending on the conditions of the
road surface. This occurs at all speeds.
The following systems are integrated into the electronic stability programme:
•Electronic Differential Lock (EDL),
•Traction control system (TCS),
•Driver-steering recommendation,
•Antilock brake system (ABS),
•Brake Assist,
•Uphill-Start off-Assist. Operating principle
The ESP switches on automatically when the engine is started and then conducts a
self-test. The ESP control unit processes data from the individual systems. It also
processes additional measurement data which are supplied by highly sensitive
sensors: the rotational velocity of the vehi
cle about its vertical axis, the lateral accel-
eration of the vehicle, the brakin g pressure and the steering angle.
The direction which the driver wishes to ta ke is determined based on the steering
angle and the speed of the vehicle and is constantly compared with the actual
behaviour of the vehicle. If differences exis t, such as the car beginning to skid, the
ESP will automatically brake the appropriate wheel.
The car is stabilised again by the forces which take effect when the wheel is braked.
Intervention into the brake system takes place primarily on the outer front wheel of
a vehicle which tends to oversteer (tendency for the rear of the vehicle to break
away) while occurs this is on the inner re ar wheel of a vehicle which tends to under-
steer (tendency to shift out of the curve). This braking control cycle is accompanied
by noises.
The ESP operates in combination with the ABS ⇒page 185, “Antilock brake system
(ABS)”. If there is a fault in the ABS system, the ESP also does not operate.
The ESP warning light ⇒page 32 lights up in the instrument cluster when there is a
fault on the ESP.
Switching off
You can switch the ESP off and on again as you wish, by pressing the button
⇒ fig. 184 . The ESP warning light ⇒page 32 lights up in the instrument cluster
when the ESP is switched off.
The ESP should normally always be switched on. It may be good practice in certain
exceptional cases, such as when you wish to have wheel slip, to switch off the
system.
Examples:
Fig. 184 ESP switch
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Intelligent Technology
182
•when driving with snow chains
•when driving in deep snow or on a loose surface
•when it is necessary to rock a ca r free when it has become stuck.
then you should switch on the ESP again.
WARNING
It is also not possible for the ESP to overcome the physical limits of the
vehicle. Even if a vehicle fitted with ESP you should still always adapt your
style of driving to the condition of the road surface and the traffic situation.
This particularly applies when driving on slippery and wet roads. The
increased safety offered must not tempt you to take greater risks than other-
wise - risk of an accident!
Note
•All four wheels must be fitted with the same tyres in order to achieve problem-
free operation of the ESP. Differing rolling circumferences of the tyres can lead to an
undesirable reduction in the engine output.
•Changes to vehicle (e.g. on engine, on the brakes, on chassis or other assign-
ment of tyres and wheels) can influence the function of the ESP ⇒page 229,
“Accessories, changes and replacement of parts”.
Electronic Differential Lock (EDS)*
The electronic differential lock pr events an individual wheel from
slipping.
Models fitted with ESP are equipped with electronic differential lock (EDL).
General
The EDL makes it much easier, and sometimes at all possible, to start off, accelerate
and climb a steep hill when the conditio ns of the road surface are unfavourable. Operating principle
The EDL is activated automatically, that is without any action on the part of the
driver. It monitors the speeds of the driven wheels with the aid of the ABS sensors.
Should only
one drive wheel begin spinning on a slippery surface there will be an
appreciable difference in the speed of the driven wheels. The EDL function brakes
the slipping wheel and the differential transmits a greater driving force to the other
driven wheel. This control proces s is also accompanied by noises.
Overheating of the brakes
The EDL switches off automatically if unusually severe stresses exist in order to
avoid excessive heat generation in the disc brake on the wheel which is being
braked. The vehicle can continue to be driven and has the same characteristics as a
vehicle not fitted with EDL.
The EDL switches on again automatically as soon as the brake has cooled down.
WARNING
•Depress the accelerator carefully when accelerating on uniformly slip-
pery road surfaces, such as ice and sn ow. The driven wheels might still spin
despite the EDL and affect the stability of the vehicle - risk of an accident!
•You should always adapt your style of driving to the condition of road
surface and to the traffic situation even when your vehicle is fitted with EDL.
The increased safety offered must not tempt you to take greater risks than
otherwise - risk of an accident!
Note
•If the ABS or ESP warning light comes on, this may also indicate a fault in the
EDL. Please have the car inspected as s oon as possible by a specialist garage.
•Changes to vehicle (e.g. on engine, on the brakes, on chassis or other assign-
ment of tyres and wheels) can in fluence the function of the EDL ⇒page 229,
“Accessories, changes and replacement of parts”.
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Intelligent Technology183
Using the systemSafetyDriving TipsGeneral MaintenanceBreakdown assistanceTechnical Data
Traction control system (TCS)
The traction control system prevents the driven wheels from spinning
when accelerating.
General
The TCS makes it much easier, and sometimes at all possible, to start off, accelerate
and climb a steep hill when the conditio ns of the road surface are unfavourable.
Operating principle
The TCS switches on automatically when th e engine is started and then conducts a
self-test. The system monitors the speeds of the driven wheels with the aid of the
ABS sensors. If the wheels are spinning, the force transmitted to the road surface is
automatically adapted by redu cing the engine speed. This occurs at all speeds.
The TCS operates in combination with the ABS ⇒page 185, “Antilock brake system
(ABS)”. The TCS will not function if a fault exists in the ABS system.
The TCS warning light ⇒page 31 lights up in the instrument cluster when there is a
fault on the TCS.
Switching off
You can switch the TCS off and on again as you wish by pressing the button
⇒ fig. 185 . The TCS warning light ⇒page 31 lights up in the instrument cluster
when the TCS is switched off. The TCS should normally always be switched on. It may be good practice in certain
exceptional cases, such as when you wish
to have wheel slip, to switch off the
system.
Examples:
•when driving with snow chains
•when driving in deep snow or on a loose surface
•when it is necessary to rock a car free when it has become stuck.
then you should switch on the TCS again.
WARNING
You should always adjust your style of driving to the conditions of the road
surface and the traffic situation. The increased safety offered must not tempt
you to take greater risks than otherwise - risk of an accident!
Note
•All four wheels must be fitted with the same tyres in order to achieve problem-
free operation of the TCS. Differing rolling circumferences of the tyres can lead to
an undesirable reduction in the engine output.
•Changes to vehicle (e.g. on engine, on the brakes, on chassis or other assign-
ment of tyres and wheels) can in fluence the function of the TCS ⇒page 229,
“Accessories, changes and replacement of parts”.
Driver-steering recommendation*
The driver-steering recommendation is an additional function of the electronic
stability programme (ESP). This function indicates to the driver in critical situations
by means of slight steering wheel impulses the direction evaluated by the system,
in which the vehicle must be steered, so that it stabilizes. The driver-steering
recommendation is active when braking shar ply on different road surfaces and on
the right and left vehicle side.
Fig. 185 TCS switch
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Intelligent Technology187
Using the systemSafetyDriving TipsGeneral MaintenanceBreakdown assistanceTechnical Data
Tyre inflation pressure-control system*
The tyre inflation pressure-control system compares with the aid of the ABS sensors
the speed and also the rolling circumference of the individual wheels. If the rolling
circumference of a wheel is changed, the warning light
lights up in the dash
panel insert ⇒page 30. The rolling circumference of the tyre can change if:
•the tyre inflation pressure is too low,
•the structure of the tyre is damaged,
•the vehicle is loaded on one side,
•the wheels of an axle are loaded heavily (e.g. when towing a trailer or when
driving uphill or downhill),
•snow chains are mounted,
•the temporary spare wheel is mounted,
•one wheel per axle was changed.
Basic setting of tyre inflation pressure-control system
After changing the tyre inflation pressures or after changing one or several wheels,
a basic setting of the system must be carried out as follows.
•Inflate all tyres to the specified inflation pressure ⇒page 223.
•Switch on the ignition.
•Press button ⇒ fig. 186 for more than 2 second s. While pressing the
button, the warning light lights up. At the same time the basic values are stored,
which is confirmed with an acoustic sound and then the warning light goes out.
•If the warning light does not go out after the basic setting, there is a fault in
the system. Have the vehicle inspected by your nearest specialist garage.
Warning light
lights up
If the tyre inflation pressure of at least on e wheel is insufficiently inflated in compar-
ison to the stored basic value, the warning light
⇒ lights up.
Warning light
flashes
If the warning light flashes, there is a system fault. Have the vehicle inspected by
your nearest specialist garage.
WARNING
•When the warning light lights up, immediately reduce the speed and
avoid sudden steering and brake mano euvres. Please stop the vehicle
without delay at the nearest possible stop and inspect the tyres and their
inflation pressures.
•The driver is responsible for the correc t tyre inflation pressures. For this
reason, the tyre inflation pressures must be checked regularly.
•Under certain circumstances (e.g. sporty style of driving, wintry or
unpaved roads) the warning light can be delayed or does not light up at
all.
•The tyre inflation pressure-control system does not take away the
responsability from the driver for the correct tyre inflation pressure.
Note
The tyre inflation pressure-control system:
•does not replace the regular tyre inflatio n pressure control, because the system
cannot detect an even pressure loss,
•cannot warn in case of very rapid tyre inflation pressure loss, e.g. in case of
sudden tyre damage. In this case carefully bring the vehicle to a standstill without
sudden steering movements and without sharp braking.
Fig. 186 Button for
setting the tyre inflation
pressure control value
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Fuses and light bulbs
246
Fuse assignment in engine compartment - version 2
Certain electrical components are only st andard on certain vehicle model versions
or only suppliable as optional equipment for certain models.
No.Power consumerAmperes
F1Not assigned
F2Windshield wiper lever and turn signal light lever5
F3Measuring circuit5
F4Valves for ABS30
F5Control unit for automatic gearbox15
F6Instrument cluster5
F7Not assigned
F8Radio15
F9Phone5
F10Engine control unit, Main relay5
F11Control unit for auxiliary heating20
Fig. 225 Schematic
representation of fuse
box in engine compart-
ment - version 2
F12Control unit for CAN databus5
F13Engine control unit15
F14Ignition20
F15Lambda probe, NOx-sensor, Fuel pump relay
Glow plug system relay15 5
F16Pump for ABS30
F17Horn15
F18Amplifier for digital sound processor30
F19Front window wiper30
F20Not assigned5
F21Lambda probe15
F22Clutch pedal switch, brake pedal switch5
F23Secondary air pump
Air mass meter
Fuel high pressure pump5
10
15
F24Activated charcoal filter, exhaust gas recirculation
valve10
F25Right lighting system30
F26Left lighting system30
F27Secondary air pump
Preglowing40
50
F28Power suppy terminal 15, Starter40
F29Power supply terminal 3050
F30Te r m i n a l Xa)40
a)In order not to drain the battery unnecessarily when starting the engine, the electrical
components of this terminal are automatically switched off.
No.Power consumerAmperes
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