P0455 Evaporative Emission (EVAP) System Large Leak
 

OK guys and gals, check engine light came on the other day, so I went to advance auto. They said this code came up. My gas cap gasket looks good. What can cause this code? Engine seems to be running fine.

Thanks in advance, Mark

If you use the search function at the top of the page for your error code p0455, you will find about 7 individual threads that cover your question, and offer various suggestions on the cause.

Thanks for the insight...
 

I would have never thought to do a search on my own...

If there is anybody else out there with some useful insight I would greatly appreciate it. I have looked through the search results...all 7 of them and only 3 really pertain to this code. I have already tried all the tests on those posts to no avail. If there are any other causes I would like to hear them, otherwise I will have to start part swapping maybe change out the purge solenoid. It did pass the blow test though.

Thanks in advance again, Mark

Shrug ....

Its early and I am on my first cup of coffee.... :D
I know these aren't hhr's but...
Recently I have cured 2 Grand Prix's of this issue. After gas cap tightening, and gasket greasing didn't work, I followed the vent tube from the cap down and found a canister under the inner fender that it attaches to. This canister houses a vacuum sensor that senses the vacuum in the system. If this vacuum gets too low for whatever reason, it will throw the evap code. I simply removed the canister, blew it out good with air, reassembled and both cars have been ok for thousands of miles. See if the hhr is similar. Haven't checked myself so that burden is on you. There should be a vacuum sensor somewhere in the system :twothumbs:

As I understand it, if you get fuel in this canister it will raise issues too so do not overfill the tank. When the gas pump clicks off the first time, stop. It's full! I found no traces of fuel in either car, only dirt.

Edit 2
After the search here, I found this
http://www.youtube.com/watch?v=Qygt1...ature=youtu.be

Bring it to the dealer, its a bulletin and im pretty sure they will replace it under warranty

Thanks for the helpful replies.
 

I'll try the canister and see if that helps. I need to take my 2500 in for service this week so I'll ask about the bulletin also.

I already did the solenoid test.

9 times out of ten it is the purge system. I too look at the canister first or purge valve.

Also you can't check a cap by looking at it so I would replace it first if you have not already done so. It is the cheapest things and in time you will need one anyways so you can keep it for a spare.

When I had a leak code a few years ago, it was the purge solenoid.

Rock Auto has one for about $10.

Steve

Try the cap first.

Then the canister fits. If you have a compressor you can check it to see if it is stuck. It should pop with pressure.

If not that check the purge.

This is the order that is most often the issue. All are normally easy to change.