Always pay attention to the information in the
yellow (
Y
page 92) or red (
Y
page 100) event
windows, which are shown by the on-board
computer if the brake system is malfunction-
ing. In addition, an indicator lamp lights up in
the instrument cluster or the status area of the
on-board computer and a warning tone may
sound. Braking behaviour may change. The
pedal travel and pedal force required to brake
the vehicle may increase. Have the brake sys-
tem checked and repaired by a qualified spe-
cialist workshop.
The vehicle is equipped with the electronic
braking system (EBS) when it leaves the fac-
tory and includes the following functions:
R
ABS (Anti-lock Braking System)
R
ASR (acceleration skid control)
R
ALB (automatic load-dependent brake)
R
Hill holder
R
BAS (Brake Assist System)
The electronic control is able to relieve the
load on the service brake by activating the
continuous brake, depending on the vehicle
load and the weather conditions.
On vehicles with disc brakes on all axles, the
electronic control system monitors the tem-
perature of the disc brakes.
If the electronic control detects malfunctions,
a corresponding event window appears in the
on-board computer.
If you brake hard (emergency braking) from a
speed greater than approximately 30 mph
(50 km/h) the hazard warning lamps are
switched on automatically. The hazard warning
lamps flash at a higher frequency.
The hazard warning lamps are switched off
automatically if:
R
emergency braking is interrupted or
R
the vehicle comes to a standstill after the
emergency braking and then pulls away
again
i
If the vehicle comes to a standstill after
emergency braking, the hazard warning
lamps continue to flash at the normal fre-
quency.
Checking the compressed-air system
for leaks
G
WARNING
It is not possible to brake the vehicle if the
compressed-air brake system has a leak or
if there is insufficient reservoir pressure.
There is a risk of an accident.
Do not pull away until the required reservoir
pressures have been reached.
In the event of loss of pressure while driving,
immediately bring the vehicle to a halt in
accordance with the traffic conditions.
Secure the vehicle using the parking brake.
Have the compressed-air system repaired at
a qualified specialist workshop.
Do not let anyone enter or exit the vehicle dur-
ing the test. This avoids you mistaking pres-
sure loss from the air-sprung seats or the level
control system for a leak.
X
Stop the vehicle on a level surface.
X
Apply the parking brake.
X
Use chocks to safeguard the vehicle against
rolling away.
X
Release the parking brake.
X
Turn the key to the drive position in the igni-
tion lock.
X
Call up the
Reserve pressure
Reserve pressure
menu win-
dow in the on-board computer in the
ã
Monitoring info menu (
Y
page 80).
X
Leave the engine running until the system-
dependent reservoir pressure is shown
(
Y
page 205).
X
Switch off the engine.
X
Turn the key to the drive position in the igni-
tion lock.
X
Call up the
Reserve pressure
Reserve pressure
menu win-
dow in the on-board computer again.
If a clear pressure loss cannot be identified
in the menu window of the on-board com-
puter, then the compressed air-brake sys-
tem is free from leaks.
If a significant loss of pressure is detected,
the compressed-air brake system is leaking.
X
If the compressed-air brake system is leak-
ing, have it checked and repaired by a quali-
fied specialist workshop.
Brakes
109
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