alternator belt MERCEDES-BENZ S550 4MATIC 2008 W221 Owner's Manual

644 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
The battery is no longer charging.
Possible causes:

alternator malfunctioning

broken poly-V-belt
Stop the vehicle immediately in a safe loca-
tion.
Engage the electronic parking brake
(
page 395).
 Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise the en-
gine will overheat due to an inoperative water
pump which may result in damage to the en-
gine.
Notify an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest authorized
Mercedes-Benz Center.
There is a malfunction in the electronic
system.Have the system checked by an authorized
Mercedes-Benz Center as soon as possible.

714 Technical data
Layout of poly-V-belt drive
S 550
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4ABC* tandem pump (pump for
power-steering assistance and ABC*
chassis)
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)S 63 AMG
1Idler pulley
2Idler pulley
3Idler pulley
4Automatic belt tensioner
5Power steering pump
6Air conditioning compressor
7Crankshaft
8Coolant pump
9Generator (alternator)S 600 and S 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