My relative has a Mirage circa 2000 with a "Service engine soon" light. He showed it to his mechanic and he said that he doesn't know what is wrong with it and that the car needs to be taken to the dealership because the computer is probably broken. When I popped the hood broken, I immediately saw that a hose is disconnected from the engine and when the car is running it is making hissing sounds. I have no idea what this hose is but it is clearly visible in this picture: http://i7.photobucket.com/albums/y260/Isisdivine/CIMG2161.jpg (right of the oil cap) So the questions are:

1) what is this hose?

2) did the mechanic miss it or does he know what he's doing and this hose is unlikely to result in "check engine" light going off?


  • Are you refering to the large hose that is attached to the valve cover.Can you reference it to left,right,top, bottom of photo.
    – mikes
    Mar 12, 2012 at 1:21
  • It it the hose that is right between the oil cap and the words "16 valve". It is relatively large and the thing it is attached to is most likely the valve cover.
    – MK.
    Mar 12, 2012 at 2:28
  • It appears that there is alarger hose covering a smaller hose. Is your question where does it go or would it cause aCEL check engine light.Did you plug it back in to anything or do you hear the hissing with it reconnected?
    – mikes
    Mar 12, 2012 at 2:35
  • just to make it clear -- the picture is just something I found on the internet, it's not of the car in question. I'm talking about the large hose which goes diagonally from southwest to northeast. The plastic connector is broken so I can't reattach it. It is very clear where it goes. Question is whether it will cause the check engine light.
    – MK.
    Mar 12, 2012 at 2:40
  • OK, so this thing is probably PCV valve...
    – MK.
    Mar 12, 2012 at 2:45

1 Answer 1


Yes it will cause a check engine light.The hose is a vacum line for the PVC valve it is to ventilate fumes out of the crankcase and burn them in the combustion process.If disconnected the air fuel mixture will become very lean.Too much air not enough fuel.After reconnecting it may take a few miles for the light to reset.The broken piece in the valve cover would be the PCV valve

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