I own a 2003 ram sport 4.7. My state requires emissions testing. However, when they try to run the test, it fails saying it can't link to the on board computer. Tried a couple of places with the same reading happening. There's no check engine light on and havemt had any major problems with my truck since I bought it in 02. I replaced the proper fuse under the hood thinking that was the issue with no results. Any advice folks? Thanks!