Doesn't disconnecting the battery usually...

[jinx8402]

Reset the check engine light and reset the MPG data?

How come when I did this yesterday it did not do that? Monday I did my plugs, fuel filter and air filter after work. Yesterday morning while driving to work my CEL came on. When I got to work, I noticed I had forgotten to re-attach the white tube back to the EVAP (or is it EVP...lol...either way it's the part on the drivers side you need to remove to take off the valve cover). I figured this must have been what caused the CEL to come on. I re-attached it.

When I got back home, I decided I would disconnect the battery to reset the CEL and see if it came back on. I tried it once, disconnected the battery for 15 minutes and pumped the brake about 10 times. Started the car up and the MPG data was still there and the CEL did not go off. I took it for a quick 5 min trip and it was still on. So I did it a second time, this time leaving the battery disconnected for about an hour and pumped the brake 15-20 times. Again, hooked it up and the MPG data and CEL is still there. I am going to leave it be for a little while and see if the CEL turns off after a few days and it realizing that the tube is hooked back up.

 

[PatrickSimmons]

I would go have the codes read just to make sure that was the problem.

 

[jinx8402]

Yeah, I was going to do that actually. But, in regards to my question...shouldn't disconnecting the battery turn off the the CEL temporarily until it found something else wrong? And if I'm not mistaken the MPG data usually resets itself. I remember it doing that when I disconnected the battery to do my clockspring.

 

[gcwimmer]

Half hour battery disconnect should reset CEL, if you are still getting CEL at start up you have something else going on. Have the codes downloaded.

 

[jinx8402]

Well, I took it to AutoZone after work and it pulled the EVAP Large leak, which is what I figured. I got the guy to reset the code after a little while. He said they are not supposed to.

Back to my original question. Does anyone know why when I disconnected the battery twice it did not reset the CEL or reset the MPG data? It's almost as if disconnecting the battery did nothing.

 

[crab daddy]

I have left it unplugged for an hour and it didn't reset the cel. Over night did the trick though. (mine was due to the wife leaving the gas cap off)

 

[jinx8402]

Maybe that's what I'll do. I leave it disconnected over night and see if that resets everything. The reason why I want to do that now is to have it relearn everything since I changed alot.

 

[eastcoastLS]

I disconnected the battery all day one day and it didn't reset my mpg. Didn't have a cel though.