Page 324 of 442

324 Practical hintsWhat to do if …Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
Undervoltage
Switch off
consumers
The battery has insufficient voltage.
Turn off unnecessary electrical con-
sumers.
Visit workshop!
The battery was charged with a battery 
charger or jump started.
Have the battery checked at a service 
station. 
The battery is no longer charging.
Possible causes:
alternator malfunctioning
broken poly-V-belt
Do not forget that the brake system re-
quires electrical energy and may be oper-
ating with restricted capability. 
Considerably greater brake pedal force is 
required and the stopping distance is in-
creased.
Stop immediately and check the 
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise 
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Notify 
an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest au-
thorized Mercedes-Benz Center. Ad-
just driving to be consistent with 
reduced braking responsiveness. 
     
        
        Page 328 of 442

328 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
Except Canada:;Canada only:3
Brake fluid
Visit workshop!
There is insufficient brake fluid in the 
reservoir.
Risk of accident! Stop the vehicle and 
notify an authorized Mercedes-Benz 
Center. Do not add brake fluid! This 
will not solve the problem.
Warning!
G
Driving while these messages are displayed 
can result in an accident. Have your brake 
system checked immediately.
If there is a malfunction in the SBC brake 
system, we recommend that the vehicle be 
transported with all wheels off the ground 
using flatbed or appropriate wheel lift / dolly 
equipment.
A tow bar must be used if circumstances do 
not permit the use of the recommended 
towing methods and the vehicle requires 
towing with all four wheels on the ground.
 Towing the vehicle with all four wheels on 
the ground is only permissible for distances 
up to 30 miles (50 km) and at a speed not to 
exceed 30 mph (50 km / h). For more infor-
mation, refer to “Towing the vehicle” 
(page 381).
If the SBC brake system enters its emergen-
cy operation mode, the driver must apply 
significantly greater brake pedal pressure 
and depress the pedal much further than 
normal to obtain braking effect. If neces-
sary, apply full pressure to the brake pedal. 
Brakes may only be applied to the front 
wheels. Stopping distance is increased!
Low brake fluid in the reservoir may cause 
the braking system to fail!
Don’t add brake fluid before checking the 
brake system. Overfilling the brake fluid res-
ervoir can result in spilling brake fluid on hot 
engine parts and the brake fluid catching 
fire. You can be seriously burned.iIf 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.!Brake pad thickness must be visually 
inspected by a qualified technician at 
the intervals specified in the Service 
Booklet. 
     
        
        Page 329 of 442
329 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
?
Visit workshop!
There may be a malfunction in the:
fuel injection system
ignition system
exhaust system
fuel system
Have the measuring system checked 
by an authorized Mercedes-Benz Cen-
ter.
B 
Coolant
Check level
The coolant level is too low.
Add coolant (
page 285).
If you have to add coolant frequently, 
have the cooling system checked by 
an authorized Mercedes-Benz Center.
Warning!
G
Do not spill antifreeze on hot engine parts. 
Antifreeze contains ethylene glycol which 
may burn if it comes into contact with hot 
engine parts. You can be seriously burned.
!Do not ignore the low engine coolant 
level warning. Extended driving with 
the message and symbol displayed 
may cause serious engine damage not 
covered by the Mercedes-Benz Limited 
Warranty.
Do not drive without sufficient amount 
of coolant in the cooling system. The 
engine will overheat causing major en-
gine damage. 
     
        
        Page 331 of 442
331 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
Ï 
Coolant
Stop, engine off!
The poly-V-belt could be broken.
Stop immediately and check the 
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise 
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Notify 
an authorized Mercedes-Benz 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 Warranty.
Coolant
Visit workshop!
The cooling fan for the coolant is malfunc-
tioning.
Observe the coolant temperature dis-
play.
Have the fan replaced as soon as pos-
sible. 
     
        
        Page 333 of 442
333 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
: 
USA only:Add 1 Qt. engine oil
at next refuelingCanada only:Add 1 Liter engine oil
at next refueling
The engine oil level is too low.
Add engine oil (
page 284) and 
check the engine oil level 
(
page 283).
Engine oil level
Stop, engine off!
There is no oil in the engine. There is a 
danger of engine damage.
Carefully bring the vehicle to a halt as 
soon as possible.
Turn off the engine.
Add engine oil (
page 284) and 
check the engine oil level 
(
page 283).
Engine oil level
Reduce oil level!
You have added too much engine oil. 
There is a risk of damaging the engine or 
the catalytic converter.
Have oil siphoned or drained off. Ob-
serve all legal requirements with re-
spect to its disposal. 
     
        
        Page 334 of 442

334 Practical hintsWhat to do if …When the 
Engine oil - Visit workshop!
 
message appears while the engine is run-
ning and at operating temperature, the en-
gine oil level has dropped to approximately 
the minimum level.
When this occurs, the warning will first 
come on intermittently and then stay on if 
the oil level drops further.If no oil leaks are noted, continue to drive 
to the nearest service station where the 
engine oil should be topped to the required 
level with an approved oil.
Display symbol
Display messages
Possible cause
Possible solution
: 
Engine oil
Visit workshop!
The engine oil has dropped to a critical 
level.
Check the engine oil level 
(page 283) and add oil as required 
(page 284).
If you must add engine oil frequently, 
have the engine checked for possible 
leaks.
It may be that there is water in the engine 
oil.
Have the engine oil checked.
Engine oil level
Visit workshop!
The measuring system is malfunctioning.
Have the measuring system checked 
by an authorized Mercedes-Benz 
Center.!The engine oil level warnings should 
not be ignored. Extended driving with 
the symbol displayed could result in 
serious engine damage that is not 
covered by the Mercedes-Benz Limited 
Warranty. 
     
        
        Page 335 of 442
335 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
A 
Reserve fuel
The fuel level has dropped below the re-
serve mark.
Refuel at the next gas station 
(page 278).
Y
Hood open!
You are driving with the hood open.
Close the hood (
page 281).
F
Key
Check battery!
The SmartKey with KEYLESS-GO* batter-
ies are discharged.
Change the batteries (
page 355).
Key
not recognized!
The 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 inter-
ference
Stop the vehicle as soon as it is safe 
to do so.
Search for the SmartKey.
Otherwise the vehicle cannot be cen-
trally locked nor can the engine be 
started again after the engine is 
stopped.
The SmartKey with KEYLESS-GO* is mo-
mentarily not recognized.
Change the position of the SmartKey 
in the vehicle.
Operate the vehicle with the Smart-
Key in the starter switch if necessary. 
     
        
        Page 336 of 442
336 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
F
Key detected
in vehicle!
A SmartKey with KEYLESS-GO* left in the 
vehicle was recognized while locking the 
vehicle from the outside.
Take the SmartKey out of the vehicle.
Keyless go
Check system
The KEYLESS-GO* system is malfunction-
ing.
Visit an authorized Mercedes-Benz 
Center as soon as possible.
Key
Do not forget key
This display appears (for a maximum of 
60 seconds) if the driver’s door is opened 
with the engine shut off and no SmartKey 
in the starter switch. 
This message is only a reminder.
Insert SmartKey in the starter switch.
Take the SmartKey with KEY-
LESS-GO* with you when leaving the 
vehicle.
Remove key
!
You have forgotten to remove the Smart-
Key.
Remove the SmartKey from the start-
er switch.
Replace key
There is no additional code available for 
SmartKey or SmartKey with 
KEYLESS-GO*.
Visit an authorized Mercedes-Benz 
Center as soon as possible.