brake MERCEDES-BENZ GL320CDI 2007 X164 Service Manual

268 Controls in detail
Driving systems
Activating Distronic
You can activate Distronic when the vehi-
cle speed is between 20 mph (30 km/h)
and 110 mph (180 km/h).
When Distronic is activated the multifunc-
tion display will show a message such as
DISTRONIC 55 mph.
If Distronic has not been activated after
pressing the cruise control lever, you will
see the message
DISTRONIC Off in the
multifunction display.
In the following cases you cannot activate
Distronic:

up to 2 minutes after starting the
engine

when you brake

when you have set the parking brake

when the automatic transmission is set
to positionP, R, or N

if the ESP® is switched off

if the ESP® has switched off due to a
malfunctionSetting the current speed
Accelerate or decelerate to the desired
speed.
Briefly lift the cruise control lever in
direction of arrow1 or depress in
direction of arrow2 (
page 267).
Distronic is activated and the current
speed is set.
Remove your foot from the accelerator
pedal.Setting a higher speed
You can increase the set speed in two
ways.
iIf you do not take your foot off of the accel-
erator pedal and continue to accelerate past the
set speed, the following message will appear in
the multifunction display:
DISTRONIC Override
The distance to a slower moving vehicle in front
of you will not be set. Your vehicle speed will
then be determined only by the accelerator
pedal position.
Warning!G
If you increase the set vehicle speed, keep in
mind that it may take a brief moment until
the vehicle has reached the set speed.
Increase the set vehicle speed to a value
that the prevailing road conditions and legal
speed limits permit. Otherwise, sudden and
unexpected acceleration of the vehicle
could cause an accident and/or serious in-
jury to you and others.

269 Controls in detail
Driving systems
Adjustment in 1 mph (Canada: 1 km/h)
increments
Briefly lift the cruise control lever up to
the resistance point in direction of
arrow1 (
page 267).
Release the cruise control lever.
The vehicle speed increases in incre-
ments of 1 mph (Canada: 1 km/h).
Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly lift the cruise control lever up
past the resistance point in direction of
arrow1 (
page 267).
Release the cruise control lever.
The vehicle speed increases in incre-
ments of 5 mph (Canada: 10 km/h).
Setting a lower speedYou can reduce the set speed in two ways.
Adjustment in 1 mph (Canada: 1 km/h)
increments
Briefly press the cruise control lever
down to the resistance point in direc-
tion of arrow2 (
page 267).
Release the cruise control lever.
The vehicle speed decreases in incre-
ments of 1 mph (Canada: 1 km/h).
iThe set value is increased in 1 mph
(Canada: 1 km/h) increments each time you lift
the cruise control lever up to the resistance
point.
iThe set value is increased in 5 mph
(Canada: 10 km/h) increments each time you lift
the cruise control lever up past the resistance
point.
iThe new speed is set and the vehicle will
accelerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.
Warning!G
If you decrease the set vehicle speed, keep
in mind that it may take a brief moment until
the vehicle has reached the set speed.
Decelerate the set vehicle speed to a value
that the prevailing road conditions and legal
speed limits permit. Otherwise, sudden and
unexpected deceleration of the vehicle
could cause an accident and/or serious in-
jury to you and others.
iWhen you use the cruise control lever to
decelerate, the brake system will automatically
brake the vehicle if the engine’s braking power
does not brake the vehicle sufficiently.
iThe set value is decreased in 1 mph
(Canada: 1 km/h) increments each time you
press the cruise control lever down to the resis-
tance point.

270 Controls in detail
Driving systems
Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly press the cruise control lever
down past the resistance point in direc-
tion of arrow2 (
page 267).
Release the cruise control lever.
The vehicle set speed decreases in
increments of 5 mph
(Canada: 10 km/h).Setting to last stored speed
(“Resume” function)
Briefly pull the cruise control lever in
direction of arrow4 (
page 267).
The Distronic resumes to the last set
speed.
Remove your foot from the accelerator
pedal.
The last set speed or, if no speed is stored,
the current set speed appears in the
multifunction display for approximately
5 seconds.Deactivating Distronic
There are several ways to deactivate the
Distronic system:
Step on the brake pedal.
or
Briefly tip the cruise control lever in
direction of arrow3 (
page 267).
Distronic will be deactivated. The last set
speed will be stored in memory.
iThe set speed value is decreased in 5 mph
(Canada: 10 km/h) increments each time you
press the cruise control lever down past the
resistance point.
iThe new speed is set and the vehicle will
decelerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.
Warning!G
The set speed stored in memory should only
be set again if prevailing road conditions
permit. Possible acceleration or decelera-
tion differences arising from returning to the
preset speed could cause an accident
and/or serious injury to you and others.
iThe following message appears in the multi-
function display for approximately 5 seconds:
DISTRONIC Off.
The last stored set speed is deleted when the
engine is turned off.

271 Controls in detail
Driving systems
Setting the following distance in
Distronic
You can set the specified following
distance for Distronic by varying the time
setting between 1.0 and 2.0 seconds. Us-
ing this time setting and the current speed
of your vehicle, Distronic calculates and
sets the required following distance to the
preceding vehicle. The set distance will be
shown in the multifunction display
(
page 267).
The distance setting switch for the time
setting is located on the cruise control le-
ver on the left-hand side of the steering
column.
iThe Distronic switches off automatically
when

you step on the brake pedal

you depress the parking brake pedal
In this case, the Distronic speed segments in the
speedometer (
page 265) will go out.

the vehicle speed falls below 20 mph
(30 km/h)

the ESP® is in operation

the ESP® is switched off with the ESP®
switch (
page 107)

the ESP® has switched off due to a
malfunction (
page 441)

you set the automatic transmission toN
while driving
The Distronic speed segments in the
speedometer (
page 265) will go out and an
acoustic warning will sound.
Warning!G
Distronic switches off and releases the
brakes when the vehicle decelerates below
the minimum speed of 20 mph (30 km/h)
by operation of the system. At that time the
driver must apply the brakes in order to
reduce vehicle speed further or bring it to a
stop.
!Setting the automatic transmission toN
while driving cancels the Distronic. However, the
automatic transmission should not be set toN
while driving except to coast when the vehicle is
in danger of skidding (e.g. on icy roads).
iDepressing the accelerator pedal does not
deactivate the Distronic. After a brief accelera-
tion (e.g. for passing), the Distronic will resume
the last set speed.
Warning!G
It is up to the driver to exercise discretion to
select the appropriate setting given road
conditions, traffic, driver’s preferred driving
style and applicable laws and driving recom-
mendations for safe following distance.

272 Controls in detail
Driving systems
1Distance setting switch
2To decrease distance
3To increase distance
Increasing distance
Increasing the distance setting tells
Distronic to maintain a greater following
distance to the preceding vehicle.
Turn distance setting switch1 in
direction of arrow3.Decreasing distance
Decreasing the distance setting tells
Distronic to maintain a smaller following
distance to the preceding vehicle.
Turn distance setting switch1 in
direction of arrow2.
Driving with Distronic
This section describes a number of driving
situations where special precaution is re-
quired on the part of the driver. Be pre-
pared to brake in such situations. Braking
will deactivate the Distronic system.
Warning!G
Distronic works to maintain the speed se-
lected by the driver unless a moving obsta-
cle proceeding directly ahead of it in the
same travel direction is detected (e.g. fol-
lowing another vehicle ahead of you at your
set distance).
This means that:

Your vehicle can pass another vehicle
after you have changed lanes.

While in a sharp turn or if the preceding
vehicle is in a sharp turn, Distronic could
lose sight of the preceding vehicle. Your
vehicle could then accelerate to the
previously selected speed.
Distronic regulates only the distance be-
tween your vehicle and those directly ahead
of it, but does not register stationary objects
in the road, e.g.:

a stopped vehicle in a traffic jam

a disabled vehicle

an oncoming vehicle
The driver must always be alert, observe all
traffic and intercede as required by means
of steering or braking the vehicle.
Warning!G
Distronic should not be used in snowy or icy
road conditions.

273 Controls in detail
Driving systems
The most likely cause for a malfunctioning
system is a dirty sensor (located behind
the hood grille), especially at times of snow
and ice or heavy rain. In such a case,
Distronic will switch off, and the message
DISTRONIC currently unavailable – See
Operator’s Manual
appears in the multi-
function display.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic* system
sensor cover” (
page 430).Turns and bends
In turns or bends, Distronic may not detect
a moving vehicle in front, or it may detect
one too soon. This may cause your vehicle
to brake late or unexpectedly.Offset driving
A vehicle traveling in your lane but offset
from your direct line of travel may not be
detected by Distronic. There will be insuffi-
cient distance to the vehicle ahead.
iIf the message DISTRONIC available
again
appears during driving the dirt (e.g.
slush) has dissolved; Distronic works again, if
you reactivate it (
page 268).

274 Controls in detail
Driving systems
Lane changing
Distronic has not yet detected the vehicle
changing lanes. There will be insufficient
distance to the lane-changing vehicle.Narrow vehicles
Because of their narrow profile, the vehi-
cles traveling near the outer edges of the
lane have not yet been detected by
Distronic. There will be insufficient
distance to the vehicles ahead.Distance warning function*
When Distronic* is deactivated, this
function will continue to warn you when
recognizing a stationary obstacle or a
slower vehicle moving in your vehicle’s
path and the danger of a collision exists:

The distance warning lampl in the
instrument cluster comes on.

An intermittent warning will sound if
necessary.
If these warnings are issued, you must
brake manually to maintain a safe distance
and avoid a collision with the preceding
vehicle.
When pressing the brake pedal, the warn-
ing sound ceases. The warning sound will
also cease when the distance to the
preceding vehicle is sufficient again with-
out applying the brakes. In this case, the
distance warning lamp will also go out.

275 Controls in detail
Driving systems
Switch on the distance warning
function in the control system
(
page 186).
Downhill Speed Regulation (DSR)For more information, see “Off-road driv-
ing” (
page 357).
The DSR is an aid for driving downhill. DSR
regulates your vehicle’s speed when driv-
ing downhill to the value set in the control
system (
page 186). The steeper the
downhill gradient is, the greater the brake
application. On flat road surfaces, DSR
brakes only slightly or not at all.
DSR regulates the vehicle’s speed in auto-
matic transmission positionsD, orR.
You can drive slower or faster than the set
speed at any time by braking the vehicle or
depressing the accelerator pedal.
Warning!G
If the distance warning lampl in the in-
strument cluster comes on while driving
and/or an intermittent warning sounds,
immediate attention on the part of the driver
is required. As required by the traffic
situation, apply the brakes and navigate
around a possible obstacle. However, do not
drive by relying on the distance warning
function, as this will result in an emergency
braking application. This will not always
enable you to avoid a collision, especially
when traveling on varying road surface
conditions and with varying driver reaction.
Complex driving situations are not always
fully recognized by the distance warning
function. This could result in wrong or miss-
ing distance warnings.Warning!G
Downhill Speed Regulation is a convenience
system designed to assist the driver during
vehicle operation. The system must be set
to be appropriate for the topographical and
weather conditions encountered which can
change quickly. The driver is and must
remain at all times responsible for the vehi-
cle speed and for safe brake operation.
Depending on the programmed speed
(
page 186), actual vehicle speed and gra-
dient, switching on the DSR while driving
can cause the vehicle to slow down rapidly
and you may hear a sound which is caused
by the activation of the vehicle’s brake sys-
tem through the DSR. Sudden and unex-
pected deceleration can result in loss of
vehicle control, causing an accident and/or
serious personal injury to you and others.
Do not switch on the DSR in a circumstance
where rapid deceleration could result in a
loss of vehicle control.
iIn addition, make use of the engine’s braking
effect by shifting the automatic transmission
into a lower gear.

276 Controls in detail
Driving systems
Switching the Downhill Speed
Regulation on/off
The switch is located on the upper part of
the center console.
Vehicles without enhanced off-road
package*
1DSR on/off
2Indicator lamp
Vehicles with enhanced off-road package*
1DSR on/off
2Indicator lamp
iWhenever DSR is switched on, DSR will use
the programmed default speed to regulate the
vehicle’s speed. The default speed programmed
at the factory is 4 mph (Canada: 6 km / h). The
default speed can be reprogrammed using the
control system (
page 186). The next time DSR
is switched on, DSR will use the newly pro-
grammed default speed to regulate the vehicle’s
speed.
Once DSR is switched on, you can adjust the set
speed using the cruise control lever
(
page 267). Keep in mind that adjusting the
set speed using the cruise control lever with DSR
switched on will not change the programmed
default speed. If DSR is switched off and then
switched on again, DSR will use the programmed
default speed.
Depending on the road surface and level of
downhill grade, the DSR may not be able to
maintain the set speed. To maintain the set
speed, apply the brakes if necessary.

277 Controls in detail
Driving systems
Switching Downhill Speed Regulation on
Press DSR switch1 (page 276).
The indicator lamp2 comes on.
The message
DSR and the set speed ap-
pear in the multifunction display.
For information on how to program the set
speed while driving, see “Adjusting Down-
hill Speed Regulation speed with DSR
switched on” (
page 278).Switching Downhill Speed Regulation off
Press DSR switch1 (page 276).
The indicator lamp2 goes out.
The message
DSR Off appears in the
multifunction display.
Warning!G
If the accelerator pedal is depressed while
the Downhill Speed Regulation is activated,
the vehicle can drive faster than the pro-
grammed set speed. You should therefore
drive downhill with particular caution as it
could otherwise lead to an accident and/or
serious injury to you or others. Keep in mind
that as soon as you remove the foot from
the accelerator pedal with the DSR switched
on, the DSR will start regulating the vehicle’s
speed including use of brakes if required.
Depending on the programmed set speed,
actual vehicle speed and gradient, the DSR
can cause the vehicle to slow down rapidly.
Sudden and unexpected deceleration can
result in loss of vehicle control, causing an
accident and/or serious personal injury to
you and others.
iThe DSR can only be switched on if the vehi-
cle speed is below 18 mph (Canada: 30 km/h).
iIf the DSR is switched on at a speed above
18 mph (Canada: 30 km/h), the message
DSR
Max. speed 18 mph
(Canada: 30 km/h) ap-
pears in the multifunction display.
iAt a speed above approximately 21 mph
(Canada approximately: 35 km/h), the DSR is
automatically switched off. The message
DSR
Off
appears in the multifunction display and an
acoustic signal sounds. For information on how
to switch DSR on again, see “Switching Downhill
Speed Regulation on” (
page 277).