alternator??? on 2002 Volkswagen Golf TDI

my car starts just fine, but when i test out the volts level on the battery it says 12.31. what does this mean. do i need a new alternator? or is it something else?

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1 answer
Sounds like the Alternator is suspect. Also check the wiring and make sure that the batter is still good, i.e. less than 4 yeas old.