05 STS P0430 (bank 2 cat efficiency)

It's your engine, transmission, driveline
kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Thu Mar 21, 2019 5:57 am

Hmm. Still on. Kind of expected it to go out yesterday or this morning. My additive is on the way so that will go in the next tank (again).

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Thu Mar 21, 2019 5:34 pm

Was out when I started it to go home today.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Wed Mar 27, 2019 6:44 pm

Got my new stuff. Also got gas tonight. No light but may get it tomorrow morning. I'll add my stuff to the tank now.
20190327_194236.jpg

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Thu Mar 28, 2019 3:18 pm

Didn't get a light this morning. But status quo would still be if I got it on startup for my drive home. Or, tomorrow morning about a mile or two into my drive in. If it makes it past that, I guess that is an improvement? We'll see. It has the additive now in this tank (2nd round).

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Mon Apr 01, 2019 5:56 am

Still no light. I'm thinking I may not see a light for the rest of this tank which has the additive. I predict that I will get a light within 3 or fewer ignition cycles on the next tank. Let's see if that holds true. If so, I may have a solution for my May inspection.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Mon Apr 01, 2019 5:38 pm

Whoops. Got a light like 8 mins into my commute home. Le sigh.

Adam
Posts: 2179
Joined: Wed Oct 23, 2013 9:50 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by Adam » Mon Apr 01, 2019 9:07 pm

Is it possible the cat is actually unable to 'catalyze' sufficiently?

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Tue Apr 02, 2019 6:08 am

That's what has been going on the entire time, or at least that was my assumption. Other than the additive about the only other thing I could attempt is replace the downstream O2 and hope that somehow makes things better. I'd make the argument that if it is truly a cat issue, replacing the O2 with a fresh one may just set a code even more frequently since the diagnostic can successfully run as quickly as possible in the widest allowed conditions. A contrary argument would be that if the O2 response was a little lazy, that could make a marginal cat more likely to fail the diagnostic. Not sure which way I lean here...

Doing the manifold/cat is major surgery and I might attempt the engine mounts at the same time if I were to embark on such a project. And looking at the steering rack removal instructions, probably the lower control arms, too. And maybe even the front diff bushing. I'd really want to do this work on a lift of some sort I think. The good news is that would be a major refresh of most front end components and probably make the car feel way better.

I guess I'd also do new O2s, or at least front ones.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Thu Apr 04, 2019 6:37 pm

Light went out this morning. Got gas tonight.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS P0430 (bank 2 cat efficiency)

Post by kevm14 » Sun Apr 21, 2019 5:52 pm

Highway driving today. Came on within 7 minutes of the return trip which was a lot of downhill coasting so maybe it didn't warm up the cat quite fast enough...

The car is due for inspection in May. Naturally this is making me nervous. Hopefully it will go back out this week and stay out until I get it inspected. Other options include: reset via tool, and/or a third bottle of that stuff.

Random note: Seems like this car will do about 22 mpg at 70 mph. My CTS-V gets a couple mpg better in all conditions.

Post Reply