It's a little sensor thingy on the intake in between the throttle plate and rubber intake hose. It is not a crank position sensor. It's pretty easy to replace and doesn't cost much.
If you got the code once chances are very high you are going to get it again. Happened when my coolant temperature sensor started to go. The CEL came on one morning driving to work. About 3 or 4 start cycles later the CEL went back out. Two days later the CEL was back on again. It is a great disadvantage to just clear the error from the ECU because the initial freeze frame data may be vital to correcting a problem that may elude you.