Hi Spook and All, I would refrain from pulling the fuse. You can clear the codes after you read all the codes that are stored. After all the codes have been read, lead in socket 2 for engine, hold button down for more than 5 seconds, light will come on, hold button down for five more seconds light will go off. Ensure fault codes have cleared by pressing test button once for more than a second, but not more than three seconds, you will get a 1-1-1 code if all codes have been cleared. The reason for doing it that way is you won't loose your adaptive memory stored in the computer. Plus you are forced to read all the codes before you can erase them. By doing it Chucks way you loose all that memory and sometimes it may take a week to get what it learned all back.