2012 MERCEDES-BENZ C-CLASS SALOON ECU

#
Ensu rethat the wheel bolts or wheel
nuts are tightened tothe prescribed
tightening torque. #
Ifyo u are not sure, do not mo vethe
ve hicle. Contact a qualified specialist
wo rkshop and ha vethe tightening tor‐
qu ech ecked immediately. #
Check the tyre pressure of the newly fitted
wheel and adjust it if necessa ry.#
Vehicles with a tyre pressure monitoring
sy stem: restart the tyre pressure monitoring
sy stem (/ page413).
Excep tion:the new wheel is an emer gency
spa rewheel. Emer
gency spare wheel Note
s onthe emer gency spare wheel &
WARNING Risk of accident caused by
incor rect wheel and tyre dimensions
The wheel or tyre size and the tyre type of
th e emer gency spa rewheel or spare wheel
and the wheel tobe replaced may dif fer. The
emer gency spa rewheel or spare wheel can
significantly impair driving characteristics of
th eve hicle.
To preve nt hazardous situations: #
Drive carefully. #
Neverfit more than one emer gency
spa rewheel or spare wheel that dif fers
in size. #
Only use an emer gency spa rewheel or
spare wheel brief ly. #
Do not deacti vate ESP ®
. #
Have the emer gency spa rewheel or
spare wheel of a dif fere nt size replaced
at the nearest qualified specialist work‐ shop. The new wheel must ha
vethe
cor rect dimensions. %
The emergency spa rewheel is secured in the
emer gency spa rewheel bag in the boot.
Obser vethefo llowing no tes on fitting an emer‐
ge ncy spa rewheel:
R Check the tyre pressure of the emer gency
spa rewheel fitted. Co rrect the pressure as
necessar y.
R The maximum permissible speed with an
emer gency spa rewheel fitted is 80 km/h.
R Do not fit th e emer gency spa rewheel with
sn ow ch ains.
R Replace the emer gency spa rewheel af ter six
ye ars at the latest, rega rdless of wear. 424
Wheels and tyres
Internal use only

Display messages
Possible causes/consequences and M
MSolutions &
WARNING Risk of injury or death when using a child restra int sy stem while the front passenger airbag is
enabled
If yo u secure a child in a child restra int sy stem on the front passenger seat and the front passenger airbag is
enabled, the front passenger airbag can deploy in theeve nt of an accident.
The child could be stru ck bythe airbag. #
Ensure, bo thbefore and during the journe y,that thest atus of the front passenger airbag is cor rect.
NEVER use a rear wa rdfacing child restra int on a seat pr otected byan ACTIVE AIRB AGin front of it, DE ATH or
SERIOUS INJU RYtotheCH ILD can occur. #
Stop theve hicle immediately in accordance with the traf fic conditions. #
Makesure that no objects are trapped under the front passenger seat. #
Check thest atus of automatic front passenger airbag actuation (/ page 48).#
If necessar y,consult a qualified specialist workshop immediatel y.
PRE-SAFE inoperative See
Owner's Manual *
The PRE‑SAFE ®
functions are malfunctioning. #
Consult a qualified specialist workshop. 448
Displaymessa ges and warning/indicator lamps
Internal use only

Ve
hicle Display messages
Possible causes/consequences and M
MSolutions
d Vehicle is operational
Switch off ignition before
exiting *Y
ou are leaving theve hicle in a ready-to-drive state. #
When you lea vetheve hicle, switch off the ignition, secure theve hicle against rolling away and take theke y with
yo u. #
Ifyo u do not lea vetheve hicle, switch off the electrical consumers, e.g. the seat heating. Otherwise, the12 V
battery may dischar geand it will then be possible tostart theve hicle only with the aid of a second battery
(s ta rting assis tance).
ï Check trailer hitch lock *T
he trailer hitch is not operational during a journey with a trailer. &
WARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivel mo vement and do not re-couple the trailer until thewa rning/indicator lamp goes out. #
Initiate a new swivel mo vement (/ page 237). #
When the display message disappears, couple up the trailer and drive on.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. 456
Display messages and warning/indicator lamps
Internal use only

Display messages
Possible causes/consequences and M
MSolutions #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe
unlo cked ball nec k. #
Consult a qualified specialist workshop.
*T he trailer hitch will not be operational when theve hicle is stationar y. #
Uncouple the coupled trailer and secure it against rolling away. #
Ifth e ball neck has been folded in: unlockthe ball neck (/ page 237). #
Swivel the ball neck into the end position manually and let it engage. #
Ifth e ball neck has been folded out: unlockthe ball neck (/ page 237). #
Swivel the ball neck beneath the bumper manually and let it engage.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe
unlo cked ball nec k. #
Consult a qualified specialist workshop.
Ù Steering malfunction
Increased physical effort
See Owner's Manual *T
he po werst eering assis tance is malfunctioning. &
WARNING Risk of an accident due toaltered steering characteristics
If th e po wer assi stance of thesteering fails partially or comple tely, you will need touse more forc eto steer. #
If safe steering is possible, drive on carefully. Display messages and
warning/indicator lamps 457
Internal use only

Display messages
Possible causes/consequences and M
MSolutions
Auxiliary battery malfunc-
tion *T
he auxiliary batteryforth e transmission is no longer being charge d. #
Consult a qualified specialist workshop. #
Untilthen, alw ays select park position jmanually before you swit choff the engine. #
Before leaving theve hicle, apply the electric parking brake. Brakes
Display messages
Possible causes/consequences and M MSolutions
! Parking brake See Owner's
Manual *
The yellow ! indicator lamp is lit. The elect ric pa rking brake is malfunctioning.
To appl y: #
Switch the ignition off and switch it back on. #
Apply the electric parking brake manually (/ page183).
If it is not possible toapply the electric parking brake: #
Consult a qualified specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away.
* The yellow ! indicator lamp and there d! indicator lamp are lit. The elect ric pa rking brake is malfunction‐
ing.
To release: Display messages and
warning/indicator lamps 465
Internal use only

Display messages
Possible causes/consequences and M
MSolutions #
Switch the ignition off and switch it back on. #
Release the electric parking brake manually (/ page183).
or #
Release the electric parking brake automatically (/ page183).
If it is still not possible torelease the electric parking brake: #
Do not continue driving. Consult a qualified specialist workshop.
* The yellow ! indicator lamp is lit and there d! indicator lamp is flashing. The electric parking brake is mal‐
functioning.
The electric parking brake could not be applied or released. #
Swit chthe ignition off and switch it back on.
To appl y: #
Release and then apply the electric parking brake manually (/ page183).
To release: #
Apply and then release the electric parking brake manuall y.
If it is not possible toapply the electric parking brake or there d! indicator lamp continues toflash: #
Do not continue driving. Consult a qualified specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away. 466
Display messages and warning/indicator lamps
Internal use only

Display messages
Possible causes/consequences and M
MSolutions
* The yellow ! indicator lamp is lit and there d! indicator lamp flashes for appro ximately ten seconds af ter
th e electric parking brake has been applied or released. It then remains lit or goes out. The electric parking brake is
malfunctioning.
If th ech arge leve l is too lo w: #
Char gethe12 V batter y.
To appl y: #
Switch the ignition off.
The electric parking brake will be applied automaticall y.
If yo u do not wantthe electric parking brake tobe applied, e.g. at an automatic car wash or when theve hicle is
being towe d, lea vethe ignition switched on. This does not include having theve hicle towe d with there ar axle
ra ised.
If th e electric parking brake is not applied automatically: #
Switch the ignition off and switch it back on. #
Release and then apply the electric parking brake manually (/ page183).
If it is still not possible toapply the electric parking brake: #
Consult a qualified specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away. Displ
aymessa ges and warning/indicator lamps 467
Internal use only

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
ï Tr ailer tow hit chwarning
lamp *T
hered trailer hitch warning lamp is lit.
The trailer hitch is not operational. &
WARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivel mo vement and do not re-couple the trailer until thewa rning/indicator lamp goes out. #
Notethe messages on the multifunction displa y.Engine
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
ÿ Coolant warning lamp *T
he red coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The coolant le vel is too low
R The air supply tothera diator is obstructed
R The radiator fan is faulty 502
Display messages and warning/indicator lamps
Internal use only