
330If and when
Several warning and control lamps should light up for a few seconds when
the ignition is switched on, signalling that the function is being verified.
They will switch off after a few seconds.
Checking the bulbs of a trailer
For vehicles with the factory fitted towing bracket, certain trailer lights are
also controlled if the power socket is correctly connected.
A fault on a trailer turn signal is indicated on the instrument panel by the
turn signal blinking twice as fast ( or ) ⇒ page 95.
● General fault of all turn signals on one side.
● Fault in one tail light (on some models, also the registration light).
● Fault in two brake lights.
WARNING
If the warning lamps and messages are ignored, the vehicle may stall in
traffic, or may cause accidents and severe injuries.
● Never ignore the warning lamps or text messages.
● Stop the vehicle safely as soon as possible.
CAUTION
Failure to heed the control lamps and text messages when they appear may
result in faults in the vehicle.
Note
A fault in the LED on the tail lights will not be indicated. However, if the fault
affects all the LEDs then this will be indicated by the control lamp . Information for replacing bulbs
Checklist
To replace a bulb, carry out the following operations always in the order giv-
en ⇒
:
Park the vehicle a safe distance from traffic and on suitable ground.
Connect the electronic parking brake ⇒ page 184.
Turn the light switch to position 0 ⇒ page 95.
Move the gear lever into the neutral position ⇒ page 95.
Automatic gearbox: move the selector lever to position P ⇒ page 175.
Stop the engine and remove the key from the ignition ⇒ page 171.
Manual gearbox: Select a gear ⇒ page 175.
Wait until all of the vehicle interior lights are turned off ⇒ page 95.
Allow the corresponding bulb to cool. Visually inspect fuses to see if any are blown ⇒ page 325.
Replace the bulb according to the instructions ⇒
. Bulbs should only
be replaced by new identical models. Bulb information is displayed on
the bulb socket or on the bulb itself.
In general, never touch the bulb glass directly. The heat of the bulb
would cause the fingerprint to evaporate and condense on the reflector.
This will impair the brightness of the headlight.
Check if the new bulb is working. If the bulb is not working, it may not
have been correctly fitted, it could be damaged or the connector may
not be correctly connected.
Every time a bulb for the headlights is replaced, visit a specialised
workshop to check the headlights.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.

331
If and when
WARNING
Failure to follow the checklist prepared for your own safety could lead to
accidents and severe injuries.
● Always complete the operations given in the checklist and observe
the general rules of safety.CAUTION
Always remove and fit headlights carefully to avoid damage to the paint-
work and other vehicle parts.
To replace halogen headlight bulbs
Fig. 205 In the engine
compartment: Left-hand
side headlight lining. A
dipped beam headlights,
B daytime driving lights
and C main beam head-
lights and side lightsFig. 206 Left headlight
There is no need to remove the headlight to replace bulbs.
Complete operations only in the sequence given:
Fig. 205, Fig. 206 ABCTurn signals (small lamp holder)Dipped beam head-lightsDaytime driving lightMain beam headlightsSide lights
1.Always take the checklist into account and take the necessary actions ⇒ page 330.2.Open the bonnet ⇒ page 278.
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333
If and when
To replace the xenon headlights bulb
Fig. 207 In the engine
compartment: Turn signal
cover
Fig. 208 Turn signal
lamp holder 1 and turn-
ing light 2
There is no need to remove the headlight to replace bulbs.
Complete operations only in the sequence given:
Turn signals 1Turning lights 2
1.Always take the checklist into account and take the necessary ac-
tions ⇒ page 330.
2.Open the bonnet ⇒ page 278.
3.Rotate the cover ⇒ Fig. 207 in the direction of the arrow and remove
it.
4.
Rotate the lamp holder 1⇒ Fig. 208 to the left all the way
and pull it out backwards with
the bulb.Press the wire clip downwards
and pull the lamp holder 2
⇒ Fig. 208 out with the bulb.
5.Depending on the model, the bulb is removed directly from the
lamp holder or it may need to be rotated and then removed.
6.Replace the faulty bulb by a new identical bulb.
7.Place the bulb holder in the
headlight and rotate to the right
all the way.Place the lamp holder in the
headlight and pull the wire clip
upwards until it clicks into place.
8.Rotate the cover ⇒ Fig. 207 in the opposite direction to the arrow as
far as it will go.
Always seek the help of a specialist when changing the Xenon dipped beam
and main beam headlamps ⇒ in Introduction on page 329.
Note
The illustrations show the left hand headlight. The structure of the right
hand side headlight is symmetric.
Safety FirstOperating instructionsPractical tipsTechnical Specifications

340If and when
Starting assistance
Introduction
If the engine fails to start because of a discharged battery, the battery of an-
other vehicle can be used to start the engine. Before starting, check the
magic eye on the battery ⇒ page 291.
For starting assistance, jump lead cables conforming to the standard
DIN 72553 are required (see the cable manufacturer instructions). The jump
lead cable must be at least 25 mm 2
in section (0.038 inches 2
) for petrol en-
gines, and 35 mm 2
(0.054 inches 2
) for diesel engines.
For vehicles whose battery is not in the engine compartment, the jump
leads should only be connected to the starting assistance connection
points in the engine compartment.
Additional information and warnings:
● Starter assist systems (Start-Stop function) ⇒ page 195
● Working in the engine compartment ⇒ page 278
● Selective Catalytic Reduction (AdBlue) ⇒ page 274
● Vehicle battery ⇒ page 291
WARNING
Incorrect use of jump leads and incorrectly jump starting could cause the
battery to explode resulting in serious injury. Please observe the follow-
ing rules to minimise the risk of a battery explosion:
● All work involving the vehicle battery and electrical system can cause
corrosion, fire and serious electric shocks. Always read and take into ac-
count the safety warnings and standards before beginning work on the
battery ⇒ page 291, Vehicle battery.
WARNING (Continued)
● The battery providing current must have the same voltage (12V) and
approximately the same capacity (see markings on battery) as the flat
battery.
● Never charge a frozen or recently thawed battery. A flat battery can al-
so freeze at temperatures close to 0 °C (+32 °F).
● If a battery is frozen and/or has been frozen then it must be replaced.
● A highly explosive mixture of gases is released when the battery is
being charged. Always keep lit cigarettes, open flames, sparks and fire
far from the battery. Never use a mobile telephone when connecting and
removing the jump leads.
● Charge the battery only in well ventilated areas given that when the
battery is charged by outside assistance, it creates a mix of highly explo-
sive gases.
● Jump leads should never enter into contact with moving parts in the
engine compartment.
● Never switch the positive and negative poles or connect the jump
leads incorrectly.
● Note the instruction manual provided by the manufacturer of the jump
leads.
CAUTION
To avoid considerable damage to the vehicle electrical system, note the fol-
lowing carefully:
● If the jump leads are incorrectly connected, this could result in a short
circuit.
● The vehicles must not touch each other, otherwise electricity could flow
as soon as the positive terminals are connected.

341
If and when
Positive pole on the starting assistance points
Fig. 217 In the engine
compartment: positive
pole for starting assis-
tance +
On some vehicles, there is a starting assistance terminal in the engine com-
partment, under a labelled cover. How to jump start: description
Fig. 218 Diagram of con-
nections for vehicles
without Start-Stop sys-
tem
Fig. 219 Diagram of con-
nections for vehicles with
Start-Stop system
Jump lead terminal connections
1. Switch off the ignition of both vehicles ⇒
.
2. For vehicles without Start-Stop system :
Safety FirstOperating instructionsPractical tipsTechnical Specifications

342If and when
–Connect one end of the red jump lead to the positive +
termi-
nal of the vehicle with the flat battery A ⇒ Fig. 218.
– Connect the other end of the red jump lead to the positive ter-
minal +
in the vehicle providing assistance B.
– Connect one end of the black jump lead to the negative terminal
–
of the vehicle providing assistance B ⇒ Fig. 218.
– Connect the other end of the black jump lead X
to a solid met-
al component bolted to the engine block or to the engine block
itself of the vehicle with the flat battery. However, connect it to
a point as far as possible from the battery A
.
3. For vehicles with Start-Stop system :
– Connect one end of the red jump lead to the positive +
termi-
nal of the vehicle with the flat battery A ⇒ Fig. 219.
– Connect the other end of the red jump lead to the positive ter-
minal +
in the vehicle providing assistance B.
– Connect one end of the black jump lead X
to a suitable ground
terminal, a solid piece of metal in the engine block, or to the en-
gine block ⇒ Fig. 219.
– Connect the other end of the black jump lead X
to a solid met-
al component bolted to the engine block or to the engine block
itself of the vehicle with the flat battery. However, connect it to
a point as far as possible from the battery A
.
4. Position the leads in such a way that they cannot come into contact with any moving parts in the engine compartment. Starting
5. Start the engine of the vehicle with the boosting battery and let
it run at idling speed.
6. Start the engine of the vehicle with the flat battery and wait two or three minutes until the engine is “running”.
Removing the jump leads
7. Before you remove the jump leads, switch off the dipped beam headlights (if they are switched on).
8. When the engine is running, disconnect the leads in reverse or- der to the details given above.
Connect the battery clamps so they have good metal-to-metal contact with
the battery terminals.
If the engine fails to start, switch off the starter after about 10 seconds and
try again after about half a minute.
WARNING
● Please note the safety warnings referring to working in the engine
compartment ⇒ page 280.
● The battery providing assistance must have the same voltage as the
flat battery (12V) and approximately the same capacity (see imprint on
battery). Failure to comply could result in an explosion.
● Never use jump leads when one of the batteries is frozen. Danger of
explosion! Even after the battery has thawed, battery acid could leak and
cause chemical burns. If a battery freezes, it should be replaced.
● Keep sparks, flames and lit cigarettes away from batteries, danger of
explosion. Failure to comply could result in an explosion.

343
If and when
WARNING (Continued)
● Observe the instructions provided by the manufacturer of the jump
leads.
● Do not connect the negative cable from the other vehicle directly to
the negative terminal of the flat battery. The gas emitted from the battery
could be ignited by sparks. Danger of explosion.
● Do not attach the negative cable from the other vehicle to parts of the
fuel system or to the brake line.
● The non-insulated parts of the battery clamps must not be allowed to
touch. The jump lead attached to the positive battery terminal must not
touch metal parts of the vehicle, this can cause a short circuit.
● Position the leads in such a way that they cannot come into contact
with any moving parts in the engine compartment.
● Do not lean on the batteries. This could result in chemical burns.
Note
The vehicles must not touch each other, otherwise electricity could flow as
soon as the positive terminals are connected.
Towing and tow starting Introduction
When towing, always respect legal requirements.
For technical reasons, it is not possible to tow a vehicle if the battery is flat.
Additional information and warnings:
● Electronic power control and exhaust gases purification system
⇒ page 231
WARNING
A vehicle with a flat battery should never be towed.
● Never remove the key from the ignition lock. The electronic steering
lock could engage. Then the vehicle will be uncontrollable. You may lose
control of the vehicle and there is a risk of serious accident.
WARNING
When towing the vehicle, the handling and braking efficiency change
considerably. Please observe the following instructions to minimise the
risk of serious accidents and injury:
● As the driver of the vehicle being towed:
– The brake must be depressed must harder as the brake servo does
not operate. Always remain aware to avoid collision with the towing
vehicle.
– More strength is required at the steering wheel as the power steer-
ing does not operate when the engine is switched off.
● As the driver of the towing vehicle:
– Accelerate gently and carefully.
– Avoid sudden braking and manoeuvres.
– Brake well in advance than usual and brake gently.
CAUTION
● Carefully fit and remove the towline anchorage and its cover to avoid
damage to the vehicle (for example, paintwork).
● When towing, fuel could enter the catalytic converter and cause dam-
age!
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344If and when
Instructions for tow starting
In general, the vehicle should not be started by towing. Jump-starting is
much more preferable ⇒ page 340.
For technical reasons, the following vehicles can not be tow started:
● Vehicles with an automatic gearbox.
● Vehicles with an electronic parking brake, given that it is possible that
the brake will not be disengaged.
● If the vehicle battery is flat, it is possible that the engine control units do
not operate correctly.
However, if your vehicle must absolutely be tow-started (manual gearbox):
● Engage the 2nd or 3rd gear.
● Keep the clutch pressed down.
● Switch on the ignition and the hazard warning lights.
● Release the clutch when both vehicles are moving.
● As soon as the engine starts, press the clutch and move the gear lever
into neutral. This helps to prevent a collision with the towing vehicle.
CAUTION
When tow-starting, fuel could enter the catalytic converter and damage it.
Towing instructions
Tow rope or tow bar
When towing, the tow bar is the safest and vehicle friendly way. You should
only use a tow rope if you do not have a tow bar. A tow rope should be slightly elastic to avoid damage to both vehicles. It is
advisable to use a tow rope made of synthetic fibre or similarly elastic mate-
rial.
Only secure the tow rope or tow bar to the towline anchorage or specially
designed fitting.
Vehicles with a
factory fitted towing device , can only be used for towing
with a tow bar, specially designed to fit on a tow hitch ball ⇒ page 236.
Towing vehicles with an automatic gearbox
Note the following for a towed vehicle:
● Make sure the gear selector lever is in the N position.
● Do not drive faster than 50 km/h (30 mph) when towing a vehicle.
● Do not tow further than 50 km (30 miles).
● If a breakdown truck is used, the vehicle must be towed with the front
wheels raised. Note the following instructions for towing four all-wheel drive
vehicles.
Instructions for towing all-wheel drive vehicles
All-wheel drive vehicles can be towed using a toolbar or tow rope. If the ve-
hicle is towed with the front or rear axle raised, the engine must be turned
off to avoid transmission damage.
For vehicles with a double clutched DSG ®
(direct shift gearbox) the instruc-
tions for towing vehicles with an automatic gearbox apply ⇒ page 344.
Situations in which the vehicle should not be towed
In the following cases, the vehicle should not be towed but transported on a
trailer or special vehicle:
● If the vehicle gearbox does not contain lubricant due to a fault.
● If the vehicle battery is flat and, as a result, the electronic steering lock
and electronic parking brake cannot be disengaged if applied.
● If the vehicle to be towed has an automatic gearbox and the distance to
be covered is greater than 50 km (30 miles).