Has anyone else had there voltage gauge drop to zero after start-up? When I turn the key on it goes to about 12V for 5 sec and then goes to zero. I am also getting a P0622 and a P2503 code when I run the key diagnostics. Does anyone know what these codes mean and where to start looking?

 

You can do a search here on the board for those codes or on google.

I highly suggest you click on the link to the Service Manual in my sig and download them and look in there also