2012 MERCEDES-BENZ G-Class alternator

Display messages Possible causes/consequences and
M Solutions? The engine fan is defective.
X
At coolant temperatures under 248 ‡ (120 † ), drive to the next
qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. # The battery is not being charged.
Possible causes are:
R
a defective alternator
R a torn poly-V-belt
R a malfunction in the electronics
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Open the hood.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not

continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is not damaged:
X Visit a qualified specialist workshop. The battery voltage is too low.
X
Switch off electrical consumers that are not required.
X Have the battery and alternator checked at a qualified specialist
workshop. The battery has been charged or the vehicle has been jump-
started.
X
Have the battery and alternator checked at a qualified specialist
workshop. 4
Check
oil

level at
next gas station. The engine oil level has dropped to a critical level.
X
Check the oil level (Y page 211).
X If necessary, add engine oil ( Y page 213).
X Have the engine checked for leaks if the engine oil needs to be
refilled more often than usual. You have added too much engine oil. There is a risk of damaging
the engine or catalytic converter.
X
Siphon off excess engine oil until it is at the specified level.
Observe the legal requirements.172
Display messages
On-board computer and displays

Problem Possible causes/consequences and
M Solutions!
The
yellow
ABS warning
lamp is lit while the
engine is running. G
Risk of accident
ABS (Anti-lock Brake System) is deactivated due to a malfunction.
Therefore, BAS

(Brake Assist), ESP ®
(Electronic Stability Program),
EBD (electronic brake force distribution) and 4ETS are also
deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is defective, other systems, such as the
navigation system or the automatic transmission, may also be
unavailable. !
The
yellow

ABS warning
lamp is lit while the
engine is running. G
Risk of accident
The on-board voltage is too low. ABS has been deactivated due to
undervoltage.
ESP ®
, BAS, EBD and 4ETS are therefore also deactivated, for
example.
The brake

system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Switch off consumers that are not required, e.g. the rear window
defroster or interior lighting.
ABS will be available again as soon as the vehicle's on-board
electrical system voltage increases.
If the warning lamp is still on:
X Have the battery and alternator checked at a qualified specialist
workshop. !
The
yellow

ABS warning
lamp is lit while the
engine is running. You have engaged the differential locks. ABS, BAS, EBD, ESP
®
and
4ETS are deactivated.
X Disengage the differential locks.
Subsequently, ABS, BAS, EBD, ESP ®
and 4ETS are reactivated. Warning and indicator lamps in the instrument cluster
181
On-board computer and displays Z

G
WARNING
Do not place any metal objects on the battery
as this could result in a short circuit.
Use leak-proof

batteries only to avoid the risk
of acid burns in the event of an accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
! Switch off the engine and remove the
SmartKey before you loosen or disconnect
the terminal clamps. You may otherwise
destroy electronic components such as the
alternator.
! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case, have the battery
disconnected at a qualified specialist
workshop. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact a qualified specialist
workshop for further information.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Mercedes-Benz recommends that you do not
carry out work on batteries yourself, e.g.
removing or charging. Have this work
performed at a qualified specialist workshop. i
If the power supply has been interrupted,
e.g. if the battery has been reconnected,
you must carry out the following tasks:
R reset the head restraints on the front
seats (

Y page 78). Charging the battery
G
WARNING
Never charge a battery still installed in the
vehicle unless

a battery charger unit approved
by Mercedes-Benz is being used. Gases may
escape during charging and cause explosions
that may result in paint damage, corrosion or
personal injury.
A battery charger unit specially adapted for
Mercedes-Benz vehicles and tested and
approved by Mercedes-Benz is available as an
accessory. It permits the charging of the
battery in its installed position. Contact an
authorized Mercedes-Benz Center for further
information and availability.
Charge the battery in accordance with the
separate instructions for the battery charger. G
WARNING
There is a risk of acid burns during the
charging process due to the gases which
escape from

the battery. Do not lean over the
battery during the charging process. G
WARNING
Battery
acid is caustic. Avoid contact with the
skin, eyes or clothing.
! Only charge the installed battery with a
battery charger

which has been tested and
approved by Mercedes-Benz. These battery
chargers allow the battery to be charged
while still installed.
! Only use battery chargers with a
maximum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point. Battery
231
Breakdown assistance Z