My wife took her '04 Sentra 1.8 to get the bi-annual emission inspection. The technician said it would not download any information. To make sure it was not their equipment he then used a handheld unit. They gave her a 3 month extension to get it repaired. Before I take it some where to have it look at I was wondering if it could be something simple like a blown fuse. Is there anything I can check before paying someone to look at it?