Backlit by evening sun

I was out testing the camera for a problem it was giving when I noticed the Rose of Sharon, backlit by the evening sun.  All worked well with the camera this time.  On Sunday it had given an error message on a number of occasions and the image that saved to the card was extremely dark, almost black. Changing the card made no difference made no difference, but removing the Nikon GPS unit resulted in properly saved images.  Battery is next suspect.