Today the red battery warming light and red triangle came on for about 5 seconds and went off. At 10 seconds the warning lights came on and stopped on. I have a heads up display and the voltage went from 14.8 volts to 11.6 I drove home but no change in the charge voltage.
i can see the belt from the top on the engine so its not a broken belt so I'm thinking it's the alternator.
Does anyone have any comments as to if I am right or wrong

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2009 XF 3 ltr V6 S (added by GGG)

 

Did the voltage decreased gradually or dropped sharply and stayed? If it's former then I'd say it's an alternator; if it's latter then it could be a voltage regulator, or a computer... In any case I'd suggest you talk to a dealer because your car is under warranty (of course if it isn't then you have X250 and therefore it's a wrong forum anyway )

 

I've moved your question from X260 to X250 forum. This is the place to post technical questions about your model.

I've also added vehicle details to your post.

Graham

 

i realised after I posted it was wrong place thanks for moving it. As for the voltage it just just dropped there was no slow decrease in the voltage