Check engine light in 2000 Honda civic Si?

2000 Honda civic Ex check Engine Light?

• I have a check engine light that has been going on and off for a few weeks now. It will go off in about a week and than come on a few days later. The strange thing was that when I took it to get the CEL checked out at a autoshop the scanner said it couldn't find why it was on. They said take it to a Honda dealership. I'm hoping maybe somebody has had a similar experience and that they might know what's going on.

• Answer:

  Your vehicle is constantly monitoring different systems on your vehicle. Being 2000 it is OBD 2 or on board diagnostics. This means the vehicle continuously will monitor for misfires, fuel trim, catalytic converter effectiveness, oxygen sensor functionality, exhaust gas recirculation (EGR) system, evaporative emissions system etc. For most faults, the part fails instantly and you get a hard code that does not go away. It shows up to the technician with no problem. However in this case, sometimes a fault can occur, however only occasionally or even very seldom. These are all computer controlled and have set points in which to pop a CEL or not. If the error occurs, it will come on. However if it stops the light will continue to be on until you turn the key off and cycle it back on. It will recheck at this time, and if all clears then the light will disappear. I would be willing to say you have a monitor that is occasionally failing (possibly a cat converter or a oxygen sensor that could be starting to slow its response, or such a small emissions leak that is barely being picked up). A quality shop that has access to a scan tool that can monitor the sensors of the vehicle is where you would need to go. However, if you are feeling no problems at all, most of these items in question will not affect the ability for the vehicle to function in the event they completely fail. So in essence it could be something, however it sounds like everything's still ok. Good luck!