2008 MERCEDES-BENZ GL550 Owner's Manual

464 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Check tires,
then restart
Run Flat Indicator.There was a warning message about a
loss in the tire inflation pressure and
the Run Flat Indicator has not been
restarted yet.Make sure that the correct tire inflation pressure is set
for each tire.
Then restart the Run Flat Indicator (page 397).
Run Flat Indicator
InoperativeThe Run Flat Indicator is malfunction-
ing.Have the Run Flat Indicator checked by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure
Check TiresThe Run Flat Indicator indicates that
the pressure is too low in one or more
tires.Carefully bring the vehicle to a halt, avoiding abrupt
steering and braking maneuvers. Observe the traffic sit-
uation around you.
Check and adjust tire inflation pressure as required
(
page 395).
If necessary, replace the wheel (page 519).
Reactivate the Run Flat Indicator after adjusting the tire
inflation pressure values (
page 397).
Tire pressure
displayed after
driving for
a few minutes.Vehicles with Advanced TPMS*:
The tire inflation pressure is being
checked.Drive the vehicle for a few minutes.
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465 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Tire Pressure Monitor
InoperativeThe TPMS or Advanced TPMS* is
malfunctioning.Have the TPMS or Advanced TPMS* checked by an
authorized Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Inoperative
No Wheel SensorsThere are wheels without appropriate
wheel sensors mounted (e.g. winter tires).Have the TPMS or Advanced TPMS* checked by an
authorized Mercedes-Benz Light Truck Center.
Have the wheel sensors installed by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Wheel Sensor MissingVehicles with Advanced TPMS*:
One or more sensors are defect (e.g.
battery is empty).
The respective tire is indicated by
- - -
instead of the tire inflation pressure in the
multifunction display.
Have the Advanced TPMS* checked by an autho-
rized Mercedes-Benz Light Truck Center.
Have the wheel sensors installed by an authorized
Mercedes-Benz Light Truck Center.
Vehicles with Advanced TPMS*:
One or more wheels without appropriate
wheel sensors mounted (e.g. spare tire).
The respective tire is indicated by
- - -
instead of the tire inflation pressure in the
multifunction display.
Have the Advanced TPMS* checked by an autho-
rized Mercedes-Benz Light Truck Center.
Have the wheel sensors installed by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Currently UnavailableThe TPMS or Advanced TPMS* is unable to
monitor the tire pressure due to a nearby
radio interference source.As soon as the causes of the malfunction have been
removed, the TPMS or Advanced TPMS* automati-
cally becomes active again after a few minutes
driving.
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466 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
ò Replace air filter.The air filter is clogged.Have the air filter checked by an
authorized Mercedes-Benz Light Truck
Center.
#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 67).
 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:
Drive immediately to the nearest
authorized Mercedes-Benz Light Truck
Center. Adjust driving to be consistent
with reduced braking responsiveness.
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467 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 67).
Do not continue to drive.
Contact 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.
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468 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 59).
;(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.
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469 Practical hints
What to do if …
Display symbolDisplay messagePossible 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 67).
Contact an authorized Mercedes-Benz
Light Truck Center. Do not add brake
fluid! This will not solve the problem.
Warning!G
Driving with the message Check Brake
Fluid Level
displayed can result in an
accident. Have your brake system checked
immediately. 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
seriously 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.
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470 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
Ï Coolant Level
Stop car, switch engine off.The 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 67).
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)
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471 Practical hints
What to do if …
During severe operation conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
Observe the coolant temperature in the
multifunction display (
page 162).
If the temperature raises again:
Contact an authorized Mercedes-Benz
Light Truck Center immediately.
Warning!G

Driving when your engine is overheated
can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously
burned.

Steam from an overheated engine can
cause serious burns which can occur
just by opening the hood. Stay away
from the engine if you see or hear steam
coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of
the vehicle and do not stand near the vehicle
until the engine has cooled down.
!The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious damage which is not
covered by the Mercedes-Benz Limited
Warranty.
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