the check gas cap came on again. its been a few weeks since last time. it only comes on after a long drive stop car in my drive way still running. makes a tick tick noise in rear then the messages dings and shows check gas cap. first time was near 3/8 tank. today it is near 1/2 tank. purge solinoid was repacled not to long ago at 70,800 miles with codes P0496 and P0451, car has near 79800. this does not happen every time with the same drive.

 

update. car fell on it face at low throttle comeing out of works drive. like it drop a cyl. sounded subi. and i let off since it would not go. cleared up and drove fine. got home to check for pending codes got a P0455. so sould i look for leaks or what?

 

sounds like your purge valve/solenoid is sticking. IIRC other have had this issue, hope one or two will chime in

 

even tho its been replaced. like not even 12k miles ago

 

thats what it sounds like to me. i could be wrong. but i have no other ideas

 

There is a leak somewhere during the vac leak test. Here's an idea: maybe you need a new gas cap.

 

that could be true. but why isnt it on all of the time. im a mechanic in training. just dont know **** about evap and motors yet

my base had this same issue, put a gas cap on it. didnt come on for a month. then its MPG dropped to 10. spent over 2k tracing nothing. so i dont want to end up there. it ended up being a EVAP canaster leak i couldnt find. found this out after i traded it in on this

 

are you in GM's ASEP program? if so, your teacher should have the Tech2, ask to borrow it and check for EVAP codes and check in SI [Service Information] for diag checks and codes for the gas cap.. i cant remember which section it is in SI but its there to diag the EVAP/gas cap..

EVAP "Can" is under the car next to the rear suspension torsion link, it has metal wrap-around-strap on one end, with two sensors and a vapor line connected into it..

like the picture below..between the suspension and exhaust pipe..

 

Have you checked the evap vent solenoid by any chance? That could very well be causing your issue here if the purge solonoid and cap both test out ok for no leaks.

 

just in case you need it:

 

The purge solenoid is so simple to test I would just do that. Take it out... try to blow through it. It should be shut.
Literally takes just a few minutes. Then you can definitively rule that out or discover it's an issue and move on to the other stuff or replace it again.

 

He said he already replaced that, so we were just moving down the line.

 

I know but when was it replaced? Maybe I missed when it was done and new parts are bad sometimes. I've run into some myself. I just thought it was so simple it couldn't hurt instead of just assuming the new part is fine.

Edit: I see it was 12k miles ago. Again, it couldn't hurt. Some members go through 3-4 of those things until finally one stays working.

 

no im in the ASSET fords program. his instructions were to smoke test it which i cant. just ended up buying a gas cap. since he told me to check the seal and vent on it. didnt see anything wrong but it seemed loose. unfortunately it didnt come on today with the same drive its always on tuesday.

thanks for the info guys. it sucks i cant diag **** at my house and when im at work i dont have time to.

 

wtf just checked alldata and P0455 doesnot exist for 2.0L just the 2.2 and 2.4???

but found it for the 09 2.0's and its got a whole diag test with special tools yay

 

Evap purge on the manifold. Had the same issue. Makes the car stumble on run like ****

P0455 is Evap

LNF Evap Purge Selenoid - YouTube

P.S. That's me

 

^^There's quite a bit more involved in an evap system other than just a purge solenoid my man.

 

Of course there is, but I have felt the stumbling that he speaks of. Replaced the bastard twice.

Even had the P0455 twice. The evap purge selenoid is the first place to start. Always.

 

does yours idle weird? like since ive been doing drive cycles to get it to come back on. at idle its loaps once in awhile. cant make video but i dont recall if my car did this piror.

more info, car has been in shop about month or 2 ago. had the whole motor torn down for a leaking head gasket. oil not coolant. and prior to that was the evap solenoid was replaced had a CEL come on stateing to replace that. so idk if this is a result of the tear down or what.

 

I don't understand why people are so desperate to point out that there's other things than the purge solenoid. Yes, we know that. But there's so few things that are SO simple to test if they are operating properly that I don't understand why anyone wouldn't just start there. Just a couple of minutes people. Especially since it's also a well known issue. That's the only point that's trying to be made here.

 

Yes lopy idle. Backfires. Could restart and be fine. Pull the purge solenoid off and blow through it. It's a 5 min check. Worth it

 

lol.. relax big guy. He's replaced the solenoid twice already so that could be a large indication that something else in the evap system is the issue. Yes, testing the the solonoid is stupid easy, and he should of course check it again, but that's not the point some of us are trying to make here. No one that has been pointing him in another direction is anywhere near "desperate" I can assure you.

 

It's actually a faulty Evap purge design.

I'm at 51k and on my 3rd one . Once a year roughly. Sucks but GM fucked this up bad.

 

i will be replacing my vent solenoid and purge solenoid. p0455 (and p0497..again for the 3rd time)