The upstream are the ones closest to the engine. They are before the cat converter. If you have the codes cleared the light will go right out, or it will take several drive cycles to clear on its own. If you want you don't have to go to jag to have it cleared. Your local auto zone can do it for you for free, or you can purchase a generic obd2 code reader and do it yourself for about 50$.
Tuesday, November 9th, 2010 AT 8:39 PM