2007 MERCEDES-BENZ GL450 Brake

469 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagesPossible cause/consequencePossible solution
#The battery is no longer charging.
Possible causes:

alternator malfunctioning

broken poly-V-belt
Do not forget that the brake system
requires electrical energy and may be
operating with restricted capability.
Considerably greater brake pedal
force is required and the stopping dis-
tance is increased.
Stop the vehicle in a safe location or as
soon as it is safe to do so.
Apply the parking brake (page 68).
 Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Drive immediately to the nearest
authorized Mercedes-Benz Light Truck
Center. Adjust driving to be consistent
with reduced braking responsiveness.

470 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
#Battery/Alternator
Stop vehicleThe battery is defective.Stop the vehicle in a safe location or as
soon as it is safe to do so.
Apply the parking brake (page 68).
Do not continue to drive.
Notify an authorized Mercedes-Benz
Light Truck Center.
{inoperativeDownhill Speed Regulation is
malfunctioning.Have the Downhill Speed Regulation
checked by an authorized Mercedes-Benz
Light Truck Center.
2Brake wearThe brake pads have reached
their wear limit.Have the brake pads replaced as soon as
possible.
!Brake pad thickness must be visually in-
spected by a qualified technician at the intervals
specified in the Maintenance Booklet.

471 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
;(USA only)
!(Canada only)
Release
parking brakeYou are driving with the parking
brake set.Release the parking brake (page 60).
;(USA only)
3(Canada only)
EBV, ABS, ESP inoperative
See Operator’s ManualThe EBP, the ABS, and the ESP®
have switched off due to a mal-
function. The BAS is also
switched off.
The brake system is still func-
tional but without the EBP, the
ABS, and the ESP
® available.
Continue driving with added caution.
Wheels may lock during hard braking,
reducing steering capability.
Have the system checked at an
authorized Mercedes-Benz Light Truck
Center as soon as possible.
Failure to follow these instructions increases
the risk of an accident.

472 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
;(USA only)
3(Canada only)
Check
brake fluid levelThere is insufficient brake fluid
in the reservoir.Risk of accident! Stop the vehicle in a
safe location or as soon at is safe to do
so.
Apply the parking brake (page 68).
Notify an authorized Mercedes-Benz
Light Truck Center. Do not add brake
fluid! This will not solve the problem.
? (USA only)
± (Canada only)
Engine
ServiceThere may be a malfunction in
the

fuel injection system

ignition system

exhaust system

fuel system
Have the engine checked by an
authorized Mercedes-Benz Light Truck
Center.
Warning!G
Driving with the message Check brake
fluid level
displayed can result in an ac-
cident. Have your brake system checked im-
mediately. Do not add brake fluid before
checking the brake system. Overfilling the
brake fluid reservoir can result in spilling
brake fluid on hot engine parts and the
brake fluid catching fire. You could be seri-
ously burned.!If you find that the brake fluid in the brake
fluid reservoir has fallen to the minimum mark or
below, have the brake system checked for brake
pad thickness and leaks.

473 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
Ï Coolant level
Stop car, switch engine offThe coolant is too hot.
Among other possible causes
(the cooling fan could be
malfunctioning), the poly-V-belt
could be broken.Stop the vehicle in safe location or as
soon as it safe to do so.
Apply the parking brake (page 68).
Turn off the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise, the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Contact an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Do not continue to drive the vehicle with
this message displayed. Doing so could
result in serious engine damage that is
not covered by the Mercedes-Benz Limit-
ed Warranty.
(Continued on next page)

479 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
FKey
not detectedThe SmartKey with
KEYLESS-GO* is not recognized
while the engine is running
because

the SmartKey with
KEYLESS-GO* is not in the
vehicle

there is strong
radio-frequency interference
Stop the vehicle in a safe location or as
soon as it is safe to do so.
Apply the parking brake (page 68).
Search for the SmartKey with
KEYLESS-GO*.
Otherwise the vehicle cannot be centrally
locked nor can the engine be started
again after the engine is stopped.
The SmartKey with
KEYLESS-GO* is momentarily
not recognized.Change the position of the SmartKey with
KEYLESS-GO* in the vehicle.
Operate the vehicle with the SmartKey in
the starter switch if necessary.
Key
not detectedThe SmartKey with
KEYLESS-GO* is not recognized
while the ignition is switched on
(
page 41) and a door is
opened or closed and the
SmartKey with KEYLESS-GO* is
not in the vehicle.
Search for the SmartKey with
KEYLESS-GO*.
Otherwise the vehicle cannot be locked
nor can the engine be started.
Change the position of the SmartKey with
KEYLESS-GO* in the vehicle.

481 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
. 3rd brake lampThe high mounted brake lamp is
malfunctioning. This message
will only appear if a critical num-
ber of LEDs have stopped work-
ing.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Active headlamps
inoperativeThe active Bi-Xenon* headlamps
system is malfunctioning.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Brake lamp
LeftThe left brake lamp is malfunc-
tioning. A substitute bulb is
being used.Replace the bulb as soon as possible
(
page 515).
Brake lamp
RightThe right brake lamp is malfunc-
tioning. A substitute bulb is
being used.Replace the bulb as soon as possible
(
page 515).
Display malfunction
Visit workshopThe display for the lamps or the
system is malfunctioning.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Front foglamp
LeftThe left front fog lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 514).
Front foglamp
RightThe right front fog lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 514).

488 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
HTire pressure
Check tiresThe pressure is too low in one or
more tires.Check and correct tire inflation pressure as
required.
Tire pressure
Caution - tire defectOne or more tires are deflating.Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers.
If necessary, change the wheel.
Caution - tire defectVehicles with Advanced TPMS*:
One or more tires are deflating.
The respective tire is shown in the
multifunction display.Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers.
If necessary, change the wheel.
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire will cause excessive
heat build-up and possibly a fire.