Today I went to get my truck (signature pic) emissions checked which is required every other year here in Ohio, so I am thinking no problem passing because the truck has only 9,500 miles and is in awesome condition. Well I pulled up and they did the gas pressure check and it passed, and then they pulled the truck forward and proceeded to put the OBD II scanner on it to check for codes or any problems. The next thing I know the guy is asking me if I have done any modification or engine upgrades such as a tuner or something like that, I told him absolutely not even though I had taken my Hyperpac off of it prior to leaving the house. He said that it had failed because the system had been completely erased by someone, so I stood there thinking about what I had done wrong to fail this test and then it occured to me. I told him I had a cut off switch for when I put the truck in storage for the winter to keep it from dying, then the guy tells me that every time I disconnected that battery it is erasing all of the codes and that it takes time for the computer to relearn all of the driving conditions such as o2 temps, egr valve, basically everything on the truck. I had only ran the truck about 20 miles before going up to the emissions place so It didn't have time to relearn I guess, he then gives me the option to run an RPM test which I had never heard of so I agreed to it. They put the truck in neutral and revved it up to what sounded like 5,000 RPM's and then they let off completely and just shut it off right away, which I wasn't too happy with them doing that to my truck! IT PASSED FINALLY! They threw out the results for the failed computer test, and they gave me a pass slip for the RPM test and I was able to get my license plates afterwards. I am going to have the same problem with my S-10 too, because I have a disconnect on it too to keep the battery from draining. So if you have a battery disconnect on your newer vehicle, run it for at least a week before you take it to the emissions station because it won't pass! Call me a dummy but I didn't know that the cut-off would mess with the computer like that, but I have to have the disconnect otherwise I will go through about 2 batteries a year from my lights. Here's a pic f the disconnect by the way, in case you were curious.