I was troubleshooting a service engine soon light on my van when I opened the hood and saw what is most likely the cause of several problems. Something, most likely a mouse, decided to take up residence under my hood. There were several spots where it had chewed into wiring and wiring harnesses and in one of the pictures you can even see where it exposed the copper wiring. These are some of the pictures I took of what I saw.
I loosened the hood panel and didn't find a mouse, alive or dead, so evidently it doesn't live there any more.