345 Practical hints
What to do if …
Symbol messagesLeft display
Right display
Possible cause
Possible solution
# 
Battery/Alternator
Stop vehicle
The battery is malfunctioning.
The SBC brake system requires 
electrical energy and therefore has 
only limited operation. Consider-
ably greater brake pedal force is re-
quired and the stopping distance is 
increased.
Stop the vehicle as soon as it is safe to do so. 
Adjust driving to be consistent with reduced 
braking responsiveness.
Notify an authorized Mercedes-Benz Center.
Visit
workshop!
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 capa-
bility. Considerably greater brake 
pedal force is required and the stop-
ping distance is increased.
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 inoperative 
water pump which may result in damage 
to the engine. Notify an authorized 
Mercedes-Benz Center.
If it is in order:
Drive immediately to the nearest autho-
rized Mercedes-Benz Center. Adjust driv-
ing to be consistent with reduced braking 
responsiveness. 
419 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
SL 500
1Automatic belt tensioner
2ABC tandem pump (pump for 
power-steering assistance and ABC 
chassis)
3Air conditioning compressor
4Crankshaft 
5Coolant pump
6Generator (alternator)
7Idler pulley
SL 55 AMGThe SL 55 AMG has two poly-V-belts (belt 
one shown in purple/belt two shown in 
black).1Idler pulley
2Automatic belt tensioner
3ABC tandem pump (pump for 
power-steering assistance and ABC 
chassis)
4Air conditioning compressor
5Crankshaft 
6Coolant pump
7Generator (alternator)
8Idler pulley
9Automatic belt tensioner
aSupercharger
SL 600, SL 65 AMG
1Automatic belt tensioner
2ABC tandem pump (pump for 
power-steering assistance and ABC 
chassis)
3Air conditioning compressor
4Crankshaft 
5Coolant pump
6Generator (alternator)
7Idler pulley
8Idler pulley
9Idler pulley 
442 Technical termsMemory function
Used to store three individual seat, 
steering wheel and mirror positions for 
each SmartKey or SmartKey with 
KEYLESS-GO*.
MON
The Motor Octane Number for gasoline 
as determined by a standardized 
method. It is an indication of a gaso-
line’s ability to resist undesired detona-
tion (knocking). The average of both 
the MON (Motor Octane Number) and 
RON (Research Octane Number) is 
posted at the pump, also known as 
ANTI-KNOCK INDEX.
Multifunction display
Two display fields in the instrument 
cluster used to present information 
provided by the control system.Multifunction steering wheel
Steering wheel with buttons for operat-
ing the control system.
Overspeed range
Engine speeds within the red marking 
on the tachometer dial, see “Tachome-
ter” (
page 132). Avoid this engine 
speed range, as it may result in serious 
engine damage that is not covered by 
the Mercedes-Benz Limited Warranty.
Parktronic (Parking assist)*
System which uses visual and acoustic 
signals to assist the driver during park-
ing maneuvers.
Poly-V-belt drive
Drives engine-components (alternator, 
AC compressor, etc.) from the engine.Power train
Collective term designating all compo-
nents used to generate and transmit 
motive power to the drive axles, includ-
ing
engine
clutch/torque converter
transmission
transfer case
drive shaft
differential
axle shafts/axles
Program mode selector switch
Used to switch the automatic transmis-
sion between standard operation (S) 
and comfort operation (C).
SL 55 AMG with steering wheel gear-
shift control and manual shift program: 
in addition to S and C (for regular S or 
comfort C operation, see above), you 
can use MANUAL for manual shift pro-
gram