So I had my codes pulled when I got my car smogged so I can get my decals for base access here in San Diego, failed because I have a CEL, but it wasn't on when I was driving, the CEL has been off and on several times already. The code I have is the P0325 Knock Sensor 1 CKT Malfunction. What do I do to fix this, replace the sensor or is there more that I may have to fix?