confusing case of signal

[akhram]

i have a 2005 MercedesR500 and it is showing malfunction in red with a battery displayed which is saying take to workshop.

the car has been parked for a long time but., it starts fine and so is the battery. pls. advice

[kevingr]

check battery terminal is fixed fine and clean. Then check alternator, means start car and remove battery to see if car is running. If car still runs that means alternator is fine too and if it stalls and switch of that mean it was running on battery than on alternator that means you have numbered hrs of drive and rush to workshop for change of alternator.