The "EVAP" system deals with containing gasoline vapors in the tank. (Raw gasoline vapor, when released into the air, will become "smog" if conditions are right.) Usually the code is merely because the gas cap was at some time not securely tightened, or the rubber seal in the gas cap is defective. If the code doesn't reoccur, don't worry about it.

 

All the CEL codes (including the EVAP system code) as well as the speedometer problem can be explained by a short in the circuit protected by fuse 15 (see picture).

 

this forum is a little bit old.. but i thought i would post anyways.. this problem occured with my 98 honda civic cx. the on going problem pissed me off.. i couldnt find any problems but i kept blowing the number 15 fuse. with a bit of googling i came across this forum. anyways with the info i got i found the problem and fixed it. my car is lowered, i have no low profile jack so it was a pain getting it up in the air. but there is a number of wires coming out of the main harness under the intake manifold. they cross over the manifold bracket and plug onto a metal bracket. one of the wires was stripped down to bare wire and was rubbing on teh bracket. thats where my short was. in the process of taping it up i broke the wire. i haad to connect it with a connecter but problem solved... no more engine codes. no more blown fuses. everyone has been a great help on here. .thanks a million

 

This is great info RonJ! I'm saving this for future reference if this problem comes up in my car.

 

Does anyone have any tips on how to do this best, perhaps some of the methods used to repair the wires and access the area on the harness.

It seems I've tried to fix this twice now and my cel has come back.

Originally I had the VSS problem on the harness, my speedometer died and fuse 15 blew.
I could only spot 1 wire on the harness that was bared, so I followed the service bulletin repair method and it came back. Even wrapped the bracket in heat-shrink so it didn't short.

When it came back I put the car up again and re-taped the wires re-did the tubing and reset. It came back again...(days later) So I checked the code and got EVAP - (90)

I checked my gas cap and the seals were terrible. On replacing it I thought I was good to go... I reset and went on my way. Only it came back again days later.

It's showing EVAP - (90) again and I'm wondering which to check? Back to the harness? or is there a real problem with my evaporative emission control system...(other then gas cap)?

It's tough to reach in from the bottom to fix the harness so I'm reluctant to do it again, and I'm convinced the 2nd time I went at it, it was a good repair. I was sure it wouldn't be a problem again. Perhaps I was wrong...

Also, why after resetting the light upon fixing something does it take so long to return if there is still a problem. It has me thinking it's fixed when it's not.

Thanks for all the help... This forum rules!
I can't thank everyone enough for all the great advice, tips, tricks, diy's, troubleshoots.
Saves me hundreds in shop repairs.

~Cheers!

 

This is what I did, for what it's worth. I got my car up on ramps. After about an hour or so of looking for, finding, and then trying to figure out how to reach/fix the wires, I removed the manifold bracket and it was pretty easy from there. I had about three wires that I could see that were stripped. I wrapped each one separately with electrical tape and then I wrapped the entire thing with tape. Since I had the bracket off, I wrapped a piece of rubber around it and duct taped the crap out of it. Put all back together and haven't had a problem since.

 

I don't think the harness problem will cause an EVAP code. If your fuse is not blown and you have no other codes, look elsewhere. The rubber seal on the gas cap is often the cause. Or it could be a crack in one of the vapor lines. Better equipped garages have a smoke machine which blows smoke into the gas tank so they can see where the leak is.

 

Fuse 15 also protects the EVAP solenoid circuit (see diagram in my earlier post). Troubleshooting the CEL code might help, as mk says.

Read this technical service bulletin for additional tips on how to repair this common short circuit problem:

http://www.tegger.com/hondafaq/tsb/civic/x99-029e.pdf