Captron

Folks, I'm a newbie on the HHR forum with a 2009 about 130,000 miles. I've started noticing a bit louder exhaust in recent weeks from up front and I am suspecting an exhaust leak rhat I have not had time to track yet. But the car is throwing 0420 with cel on and when I read the fuel trims, and from my experience on other cars, it seems to be indicating a vacuum leak somewhere. The left is up near +18 at idle and goes immediately down with throttle. So...Can an exhaust leak (maybe manifold or manifold gasket) cause the fuel trim to behave this way and cause the 0420?

donbrew

No need to track the leak it is the flex pipe. Like this: https://www.ebay.com/itm/Direct-Flex...5U7xt-&vxp=mtr





If you are very lucky that will cure the p0420. P0420 mean the catalytic converter is not doing it's job, usually needs replacement. You can just get a whole new downpipe that includes the flex and the cat for under $200.

The exhaust leak is causing you fuel trim oddities, probably a P0171/P0172 s=oon.

Oldblue

X2, flexpipe, I prefer to replace the whole down pipe.

Captron

Thanks to you guys for helpful responses . I'm a diy guy who has self maintained my cars for years, including a couple of jags, but unfamiliar with HHR. Looking around after your feedback, it looks like that flexpipe is sort of buried in there and needing full clearance underneath to change it out. Is something I can do by getting underneath the car with handstands or best done on a lift? Not sure of this one.

Captron

Typo last post...jackstands not handstands

Oldblue

It’s an Olympic Year, handstands aside, I jack up the HHR place jackstands, under near the lca bolts

donbrew

You can get to the top 3 flange nuts from the top. You need a 24 inch extension from the bottom.

If you go the downpipe route it is a 5 bolt job + 2 gaskets and a can of CRC/WD40/rust catalyst.

Captron

a few weeks ago I posted an inquiry about my car being a little louder than normal and cel coming on with catalytic fault code. I received responses that it was likely the flex pipe needing replacement and possibly the cat too. I've looked at ebay and see whole flex/cat assemblies that bolt on for around $120. But when I go to purchase, I get notifications not for CALIFORNIA of course. This beautiful over regulated messed up state. So.....gang.....where do I buy a California approved cat assembly, how much should it be, and what is so different about it? I'm on a shoestring here, and even considering a salvage yard but hesitant to take the risk on it. CALIFORNIANS.......lets get our act together.....highest gas prices in the country, highest personal state and property taxes and bs like the emissions standards that no one else in the country has to put up with. We are nuts!

donbrew

"There ought to be a law."

What is different is that it has a C.A.R.B. label on it.

Where to buy? A seller in California.

If the cat is still under Federal warranty (check your individual status) It MUST be replaced under warranty. A 2009 might still be covered, I think it is 10 years, there is a good probability that I am wrong.

I am assuming that "catalytic fault code" means P0420?

It is illegal for a salvage yard to sell a cat.

If you have only driven in California the chances that the cat is bad are slim. I wouild try the flex pipe first.

Does the car have a C.A.R.B. label, was it originally sold in CA? That would be NU1 on the stickers on the glove box door and probably some stickers under the hood. If not, you might get away with going to a neighboring state and having it replaced there, you might need an address in that state.

Captron

Don, I am stupid when it comes to interpreting stickers and such, but I looked at the glove box sticker and can only find NU 5 in one location on the sticker, under the hood there is emissions label that states it meets federal regulations and is "California class"......

Yes, I would like to try doing just the flex pipe first, but this is unfamiliar territory for me. I do maintain my own vehicles for the most part , including significant top end work on a jaguar but looking from the top of the engine on this I see the 3 bolts holding the flex pipe on, but it appears to me to be a one piece assembly into the cat. I see no other flange fitting except to the rear of a 2nd cat or muffler assembly where I see a 2-bolt flange.

So, is the flex pipe commonly welded to the pipe going into the cat or am I just missing another set of bolts to extract that flex pipe?
And ....thank you for your help and response.

ps....i just recieved a safety recall notice on this vehicle, for the ignition switch 2 days ago.....something about key could shut off car in motion and render the airbags inoperable while you proceed with crashing into something without power.