2012 MERCEDES-BENZ G-Class ABS

Differential locks
General information Differential locks improve the traction of the
vehicle.
G
WARNING
Never drive on firm road surfaces with
differential locks engaged. Never drive on
narrow bends
with front-axle differential locks
engaged. With differential locks engaged, the
vehicle's ability to steer is severely restricted
and the danger of accidents is therefore
higher.
Do not engage or disengage differential locks
while driving on a bend. The vehicle may
otherwise make a jerking movement. You
could thus lose control of the vehicle and
cause an accident.
If you select a differential lock, ABS, 4ETS,
ESP ®
and BAS will be deactivated.
Your vehicle is equipped with a differential
lock for:
R the transfer case: this controls the balance
between the front and rear axles.
R the rear axle: this controls the balance
between the wheels on the rear axle.
R the front axle: this controls the balance
between the wheels on the front axle.
! In order to avoid damage to the transfer
case, you must operate the vehicle on a
dynamometer (1-axle dynamometer) only
if:
R the axle not driven on is jacked up
or
R the corresponding propeller shaft is
disconnected
and
R the differential lock of the transfer case
is engaged.
Otherwise, the transfer case can be
damaged. Information about differentials and
differential locks When
the vehicle drives around a corner, the
wheels on

the outside of the bend must cover
a greater distance. Therefore, the wheels turn
more rapidly than on the inside. The
differential, a transmission in the drivetrain,
balances out the different rotational speeds
and therefore enables driving through bends.
The disadvantage of a differential is that more
power is transferred to the wheels that have
the least grip. Example: a wheel on a driven
axle stands on snow-covered ground and thus
has no traction. This wheel receives the
strongest driving power from the differential,
as the force progression takes the path of
least resistance. The opposite wheel on this
axle, however, which stands on firm ground
and could therefore allow propulsion,
receives no driving power. 4ETS eliminates
this disadvantage. It provides good
steerability by automatically braking the
spinning wheel. As a result, 4ETS directs
more driving power to the wheel standing on
firm ground, which is therefore able to
provide propulsion.
ESP® and 4ETS are traction systems that are
ideal for road driving and suitable for light off-
road driving. Off-road gear LOW likewise
improves off-road capabilities.
Moreover, the more difficult conditions in off-
road driving require further measures such as
locking one or several differentials. Your
vehicle is equipped with three differential
locks:
R a central differential lock for the transfer
case,
R a differential lock for the front axle and
R a differential lock for the rear axle.
Each differential lock can be engaged with the
respective switch on the center console.
When the central differential lock for the
transfer case is locked, the speed of the front
wheels is equal to that of the rear wheels.
When the differential for the rear axle is
locked, both rear wheels turn equally fast, 148
Off-road driving systems
Driving and parking

independent of their respective torques.
Keep
in
mind that by engaging the differential
locks, vehicle steerability is severely
restricted.
For your own safety, the safety of others and
to prevent damage to your vehicle, the
differential locks must not be activated on
paved roads. Keep in mind that when driving
on firm road surfaces, the function of the
differentials is necessary and therefore they
must never be locked on firm road surfaces.
The steerability of the vehicle would
otherwise be lost and steering would no
longer be possible. For this reason, the
differential locks must be engaged
exclusively during off-road driving, and only
when activating the other driving systems
(4ETS, ESP ®
and LOW range off-road gear) is
no longer sufficient.
Activating the differential lock General information
G
WARNING
Never drive on firm road surfaces with
differential locks engaged. Never drive on
narrow bends

with front-axle differential locks
engaged. With differential locks engaged, the
vehicle's ability to steer is severely restricted
and the danger of accidents is therefore
higher.
Do not engage or disengage differential locks
while driving on a bend. The vehicle may
otherwise make a jerking movement. You
could thus lose control of the vehicle and
cause an accident.
If you select a differential lock, ABS, 4ETS,
ESP ®
and BAS will be deactivated.
Activate the differential locks:
R off-road
R to deactivate ABS, 4ETS, ESP ®
and BAS
while off-road
R when fording
For further information on driving off-road,
see ( Y page 134). The switches are located on the center
console.
:
Function indicator lamps (red)
;
Differential lock for the front axle
=
Differential lock for the transfer case
?
Differential lock for the rear axle
A
Activation indicator lamps (yellow)
!
Only activate the differential locks when:
R you are driving at walking pace.
R the driven wheels are not spinning.
R you are

not driving on a firm road surface.
i You can only engage the differential locks
when the transfer case is in LOW range off-
road gear (Y page 145).
i You can activate the differential locks in
the following order =, ?, ;.
Differential lock for the transfer case
X To engage: switch the transfer case to off-
road gear LOW

(Y page 145).
X Press switch =.
The yellow activation indicator lamp under
switch = lights

up when the transfer case
is in off-road gear LOW.
The å warning lamp in the instrument
panel lights up.
The red function indicator lamp above
switch = lights up when the differential is
locked.
In the multifunction display you see the: Off-road driving systems
149
Driving and parking Z

ABS not available Differential
Locked message.
The
å!÷ warning
lamps light up
in the instrument cluster.
The differential lock for the transfer case is
engaged.
4ETS, ESP ®
, BAS and ABS are deactivated.
The vehicle's ability to steer is severely
restricted. Drive carefully and accelerate
gently for optimum traction.
i You can now engage differential lock for
the rear

axle ? and differential lock for the
front axle ; as desired.
Differential lock for the rear axle
X To engage: press switch ?.
First, the yellow activation indicator lamp
lights up, followed by the red function
indicator lamp.
The differential lock for the rear axle is
engaged.
Differential lock for the front axle
X To engage: press switch ;.
First, the yellow activation indicator lamp
lights up, followed by the red function
indicator lamp.
The differential lock for the front axle is
engaged.
Deactivating the differential lock You can deactivate the differential locks in
the reverse order: ;, ?, =.
X
To simultaneously deactivate all
differential locks: press switch =.
Yellow activation indicator lamps A go
out. Red

function indicator lamps : go out
once the differential locks have
disengaged.
After approximately three seconds of
normal driving, ABS, 4ETS, ESP ®
and BAS
are activated.
The ABS not available Differential
Locked message disappears from the multifunction display and the
å, !
and ÷ warning

lamps in the instrument
cluster go out.
X Switch the transfer case to road gear
HIGH(Y page 145).
i If red function indicator lamps : do not
go out

when you disengage the differential
locks, bring the vehicle to a stop, while
paying attention to road and traffic
conditions, then begin driving again. The
load change can disengage the differential
locks. G
WARNING
Always remember to disengage the
differential locks when returning to drive on
paved roads, see "A few words about
differentials and differential locks". 150
Off-road driving systems
Driving and parking

Safety systems
Display messages Possible causes/consequences and
M Solutions
ESP
Inoperative See
Operator's Manual
G
Risk of accident
ESP ®
(Electronic Stability Program) is not available due to a
malfunction.
ABS (Anti-lock

Brake System), BAS (Brake Assist), EBD (electronic
brake force distribution), 4ETS (Electronic Traction System) and
the tire pressure monitor have also been deactivated.
The brake system continues to function normally, but without the
functions listed above.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. ABS
ABS not available
Differential
Locked You have engaged the differential locks.
X
Disengage the differential locks.
Subsequently ABS is reactivated. ABS
Inoperative See
Oper. Manual
G
Risk of accident
ABS and ESP ®
are not available due to a malfunction.
BAS, EBD and 4ETS have also been 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 Drive on carefully.
X Visit a qualified specialist workshop immediately. $
(USA only)
!(Canada only)
Release Parking
Brake You are driving with the parking brake applied.
X
Release the parking brake. $ (USA only)
J(Canada only)
Check Brake Fluid
Level G
Risk of accident
There is insufficient brake fluid in the brake fluid reservoir.
X Pull over as soon as it is safe to do so.
X Do not continue driving under any circumstances.
X Engage the parking brake.
X Consult a qualified specialist workshop.
X Do not add brake fluid. This will not rectify the malfunction.166
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

Problem Possible causes/consequences and
M Solutions$ (USA only)
J (Canada only)
!
The red brake system
warning lamp and the
yellow ABS warning
lamp are on while
driving. In addition, a
warning tone sounds
for about five seconds.
G
Risk of accident
EBD is faulty.
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 Drive on carefully.
X Visit a qualified specialist workshop. ÷
The yellow ESP
®
warning lamp flashes
while the vehicle is in
motion. G
Risk of accident
ESP ®
or traction control is intervening because there is a risk of
skidding or because at least one wheel has started to spin.
X When pulling away, only depress the accelerator pedal as far as
necessary.
X Ease off the accelerator pedal after pulling away.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
For exceptions: (

Y page 55).å
The yellow ESP
®
OFF
warning lamp

is lit while
the engine is running. G
Risk of accident
ESP ®
is deactivated. ESP ®
will not stabilize the vehicle if it starts
to skid or if a wheel starts to spin.
X Reactivate ESP ®
.
For exceptions: (
Y page 55).
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. 182
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Problem Possible causes/consequences and
M Solutionså
The yellow ESP
®
OFF
warning lamp
is lit while
the engine is running. You have engaged the differential locks. ABS, ESP
®
, 4ETS and BAS
have been deactivated.
X Disengage the differential locks.
ESP ®
, 4ETS and BAS are subsequently reactivated.
X Observe the additional display messages in the multifunction
display. +
The red SRS warning
lamp is lit while the
engine is running.
G
Risk of injury
The restraint systems are malfunctioning. The air bags or ETDs
may either be triggered unintentionally or, in the event of an
accident, not be triggered at all.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. G
WARNING
In the event a malfunction of the SRS is indicated as outlined above, the SRS may not be
operational.
For your safety, we strongly recommend that you contact an authorized Mercedes-Benz Center
immediately to

have the system checked. Otherwise the SRS may not be activated when needed
in an accident, which could result in serious or fatal injury, or it might deploy unexpectedly and
unnecessarily which could also result in injury. Warning and indicator lamps in the instrument cluster
183
On-board computer and displays Z

(100 km) as they only reach their full
performance after this distance.
R Do not use tires that are excessively worn
as the tire traction on wet road surfaces
decreases significantly when the tread
depth is less than 1
/ 8 in (3 mm).
R Replace the tires after six years at the
latest, regardless
of wear. This also applies
to the spare wheel.
The service life of tires depends, among other
things, on the following factors:
R driving style
R tire pressure
R distance covered Winter operation
Please bear the following in mind
Have your

vehicle winterproofed at a qualified
specialist workshop at the onset of winter.
Observe the notes in the "Changing a wheel"
section ( Y page 265).Driving with summer tires
At temperatures below 45 ‡ (+7 †), the
elasticity of summer tires and therefore also
the traction and braking capability are
reduced considerably — equip your vehicle
with M+S tires. Using summer tires at very
cold temperatures

could cause tears to form,
thereby damaging the tires permanently.
Mercedes-Benz cannot accept responsibility
for this type of damage. M+S tires
At temperatures below 45 ‡ (+7 †), use
winter tires or all-season tires. Both types of
tire are identified by the M+S marking.
Not

all tires with the M+S marking provide the
driving characteristics of winter tires. In
addition to the M+S marking, winter tires also
bear the snowflake symbol i on thesidewall. Tires with this marking fulfill the
requirements of the Rubber Manufacturers
Association (RMA) and the Rubber
Association of Canada (RAC) regarding snow
traction, and were specially developed for
driving on snow. Only these tires will allow
driving safety systems such as ABS and
ESP
®
to

function optimally in winter, as these
tires have been designed specifically for
driving on snow.
i You can obtain information about winter
tires that have been approved by
Mercedes-Benz especially for your vehicle
at any authorized Mercedes-Benz Center.
Use M+S tires of the same make and tread on
all wheels to maintain safe handling
characteristics.
i For further information about tires, see
(Y page 268). G
WARNING
M+S tires with a tread depth of less than
1 / 6 inch (4 mm) must be replaced
immediately. They are no longer suitable for
use in winter.
Always observe the maximum permissible
speed specified for the M+S tires you have
mounted.
When you have mounted the M+S tires:
X Check the tire pressures (

Y page 245).
X Restart the tire pressure monitor
(Y page 251). G
WARNING
The spare wheel and M+S tires have different
tire characteristics. Driving characteristics
can be

severely impaired when you mount the
spare wheel. There is a risk of an accident.
You should therefore adapt your driving style
and drive carefully. Have the spare wheel
replaced with a new wheel with an M+S tire
at the nearest qualified specialist workshop. 244
Winter operation
Wheels and tires