I am new to using the built in diagnostic mode on my '85 deville, but it shot out a E16 which i found in a sticky to mean generator volatge out of range. now for starters I know that I dont have a generator its an alternator. But I do get pulsing lights ie; headlights, map lights, dash lights, ect. I have been having this problem for a while now and it is very annoying to say the least. But does this mean that the alternator is bad and needs to be replaced? My service engine soon has been coming on and off recently but it doesnt stay on for long maybe 30 sec at the most. So does anyone have any tips they can share?