I was driving earlier this week and the check engine light soon light came up. Ended up getting a diagnostic test done at the dealership for $70. The codes were P0136 - O2 Sensor Performance and P0455 Evap System Large Leak Detected. The mechanic claimed it could be a loose fuel cap. So the light was removed and now 2 days later it showed up again.
Could this just be a loose fuel cap? One thing for sure is that i have to buy a Diagnostic Code Scanner now to get rid of the error. Should i just ignore it and keep clearing the error?
If your state has emmisions tests them I would fix it if not good luck mine is throwing 440 which is evap system but I found a way to make it pass emmisions
Did you actually check your gas cap?
It could also be a leak in the fuel tank fill hose or its connections, or really any kind of opening/gap/crack in any of the plumbing that connects to the fuel tank or EVAP system.
As long as you are not leaking fuel anywhere, you can ignore that check light for drivability purposes but it does get old staring at it after a while.
-------------------------------------------------
Sleeper style, they don't see it coming that way.
autozone will check/clear the codes for you so no need to buy a code scanner
First thing is change your gas cap and look under the rear of the car, there could be a loose wire that connects to the evap canister that is notorious for breaking. Replacing that wire if its broke could fix it for you.
I had to reset mine to. Ifs under the year 2000 alot of the cars you can just remove the battery and leave it out for a min and put it back in to reset it. it worked with my cavalier 96 yesterday.
It cant be a fuel leak cause im getting the best gas mileage yet. Ya ive looked at the gas cap. It seems like i can wiggle it around a bit. If anything i'd try replacing that first.
Yep, starring at that light is annoying. If a light or anything pops up when im flying im not supposed to ignore it, lol that habbit carries over to my car.
I'll check the wiring leading up to the evap canister. See if theres anything wrong there.
Mines a 2004, ill resort to disconnecting the battery if i get real annoyed with the light.. Kinda reminds me of when i was a kid and my dads car had the ebrake light on while he drove, he ended up putting a piece of cardboard over the dash to cover it. lol
Thanks for the tips everyone, and the good thing is in bc canada i dont have to do the emissions test for a lonnnnng time.
Ger B wrote:Here is a video of the gas cap. If it was this loose could that have set off the evap leak?
http://www.youtube.com/watch?v=8HXpIKpaO_k
Possibly...I'll check mine when I get back out to the parking garage on the way home. That could be just some slop in the springy "anti-gorilla tight" gizmo in there.
I never notice mine wiggling like that though (and I would if anybody would, I fill up 2x/week). When it was like that, could you actually tighten it? That would count as a large leak if it really wasn't seated/sealed properly.
-------------------------------------------------
Sleeper style, they don't see it coming that way.
I had and still have the same problem. I got a new gas lid and still the same code. Due to the weather I haven't done anything else. I'm still getting 30ish mpg on highway so...when the weather clears up here is this armpit of a state PA I will be tackling this issue.
$70 at the dealership, go tell them you want your money back.
2004 LS Cavy - everyday driver
http://temp.corvetteforum.net/c4/snakecharmer
www.myspace.com/streetdreamscarclub
Right in front of the rear axle.
Tinkles
2003 Cavalier 1SV
Bagged and Blown
I too have the P0455 code but mine is a clogged vent, the gas vapors aren't able to be released, where would this problem be located. Any help would be great
Yea I have had similar problem with mine think it was the P0455 code that was being thrown. the old guy at autozone said he thinks it was the purge valve...which supposedly is what allows excess gas fumes to be removed from the cylinders and put back in the tank... I really don't know much about the situation, just what the guy said. Had my cousin check it out at the shop he works at, came up as EVAP leak but really never done anything after that...6 months now since it started, it comes on and goes off every so often...car runs fine, MPG still the same...but will check that wire soon.
you spent 70 bucks on getting codes scanned and cleared? you know you can buy a code scanner (which does this for you) for 80 right?
nwuonline.com
Proud member on JBNW.org
JBO member since 2004
Checked the canister while the car was getting inspected, all looked fine. Told guy at garage who recommended another garage to do a smoke test. Stopped there and guy quoted me $49.99 for just the smoke test through the emission system. NO WAY I will ever pay that so...guess the light will stay on.
2004 LS Cavy - everyday driver
http://temp.corvetteforum.net/c4/snakecharmer
www.myspace.com/streetdreamscarclub
you keep talking about your gas mileage.... IT'S NOT A GAS LEAK!
The EVAP system requires the gas tank to be air tight, it forces the gas vapors through the EVAP lines to get sucked into the engine and burnt up rather then vented out into the atmosphere. EVAP leak means your leaking gas vapor into the air, not puddles of fuel on the ground.
Large leaks are almost always the gas cap being loose or the seal damaged, the only other time you really see large leak is when mice have chewed through a line of a part of the system is literally broken open. If you take it to a shop and pay for an hour of diagnosis they will hook up a smoke machine that dumps smoke through the system and pressurizes it slightly, then then look it over and find where the smoke is coming from, find the smoke and you find your leak.
I'm saying about gas mileage because of the light being on period...i know that I'm not leaking gas or I would see this on the gas gauge or smell and or see it.
I'm pretty sure in my last post I explained that I looked into the smoke system thus making your post useless. I also posted earlier in the thread that I changed the gas cap.
2004 LS Cavy - everyday driver
http://temp.corvetteforum.net/c4/snakecharmer
www.myspace.com/streetdreamscarclub
I am having this same issue with my 2004 cavalier. I have replaced the fuel filler neck, both of the solenoids the one under the car near the gas tank and the one up in the engine bay that is bolted to the power steering pump. I checked the wires and the connectors on the purge solenoid that is under the car and also did a soap test on all the hoses. I know there isn't a hell of a lot of pressure there but maybe enough to make a bubble. Got nothing. I even went as far as taking that purge solenoid apart and super glueing all the gaps so I can't leak. Used a volt meter and did a continuity test was good. Had some one wiggle wires also as I was testing. Connection was there. Still having the problem. My fuel filler neck was in rusty so I replaced it. Also replaced the fuel cap while I was at it. Now it has been 300 miles since I changed the neck no check engine light. So I thought I could bring the car for a inspection. Yeah right failed NYS emission's because the readiness monitors weren't complete. This has been a ongoing problem with the car for 2 years. Have one more year left to pay on the car then she is gone..... No more GM products newer than 93. GM rushed the last 2 years of the cavalier to make room for the cobalt.
I am very disapointed with the car. Runs good but if you live in a state with emission testing to pass inspection you are up @!#$ creek without a paddle or a boat. I have had earlier Cavaliers that never in 200,000 so much as lit a check engine light.
I love Chevrolet to death but not going to buy a new one. Will buy a older Chevy and restore it.
there are 2 evap valves, a vent valve which equalized atmosperic pressure and tank pressure, and the second is the purge valve which basically puts fuel vapors from the tank back through the engine to be burned. i have replaced way more vent valves than purge valves so check into the vent valve guys. hope this helps some of you
Which one is the vent valve?Is that the one on the sending unit or the one that is near the vapor canister?
vent valve is the 1 closest to the fuel tank purge valve is usually in the engine bay
