Hi i am new here and i have a problem. I replaced the spark plug of my Odyssey and the check engine signal came on. I disconnected the negative cable then put it back on- the check engine signal went away but after one day it came back.. Can anyone assist regarding this matter?

 

Well before anyone can help the first thing that needs to be done is to obtain the code that is stored in the PCM. Usually Autozone will do a free diagnostic check where they will retrive the code from the PCM. without that codes its basically a shot in the dark.

We can however cover the basics. Does the car run rough since you put the plugs in?

What brand plugs are they? Bosch.

Are all the plug wires snapped in tight. and in proper order?
or if it has coil packs (i can't remember) are they plugged in?

 

Why only one spark plug? Not that it matters. Was there a problem with it? Did you gap the spark plug properly?

I believe the check engine light can mean there is an error code related to your emissions system (oxygen sensors). This might be related to your spark plug, as it may not be firing properly and putting too much unburned fuel in your exhaust stream.

 

Its very possible it may just be a misfire code. the only way to go about this is to get the actuall code. We can guess all day but why be wrong when we can be right.