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Discussion Starter #1
I have a 2005 Cadillac CTS 3.6l V6. And my check engine light is giving me P0420 and P0430 codes. I don't know whether to replace the catalytic converters or change the 02 sensors.
 

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'05 CTS-V
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The point of the codes is to tell you the cats need to be replaced. If you want to spend less money and replace the O2 sensors first, on the slight chance that doing so will clear the codes, go for it. But chances are you'll end up replacing the cats, too. Look 'em up on rockauto.com when it comes time for that - much more affordable options than going with new OEM cats.
 

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2005 CTS/ 2008 DTS/ 2008 STS V8 N*/ 2011 CTS4 ALL W/D Pearl
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I have a 2005 Cadillac CTS 3.6l V6. And my check engine light is giving me P0420 and P0430 codes. I don't know whether to replace the catalytic converters or change the 02 sensors.
How did you make out?
 

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Discussion Starter #6
hevenz said:
What cats did you use? Any bad shit happen when u threw the codes? (Sluggish acceleration...)
Bought the cats at rockouto.com for $257 for both. And what do you mean when I threw the codes?
 

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2007 CTS
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Engine code P0420 mystery.

Okay so my check engine light pops on and I have Onstar conduct a diagnostic check. The code reveals a possible bad catalytic converter.. I also search online and pretty much the same information. Here's the issue: the light goes off and stays off, that is until I fill my tank up with gas! What is that? It states a bad fuel mixture of some sort, yet my car rides just fine with no loss of power. Again the light goes off on it's own but comes on after refuelling, then at about a half a tank goes back off! Anyone?
 

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2005 CTS/ 2008 DTS/ 2008 STS V8 N*/ 2011 CTS4 ALL W/D Pearl
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How many Catalytic convertors replaced on this forum?

How many 2004-2007 3.6 or 2.8 have had to replace their cat or cats?

Has anyone been able to have LONG TERM SUCCESS with an after market cat? I mean no engine code after a year or so?

From what I understand most people that have used a walker or others have had the P0430 or P0420 come back after some time and that's with direct fit, apparently the cut and glue ones :canttalk: are very insufficient?
 

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Discussion Starter #11
It is better to get your direct fit catalytic converters from rockauto.com. I had both codes and have felt a real difference with the ride. Haven't had any issues yet.
 

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2005 CTS/ 2008 DTS/ 2008 STS V8 N*/ 2011 CTS4 ALL W/D Pearl
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Re: How many Catalytic convertors replaced on this forum?

It is better to get your direct fit catalytic converters from rockauto.com. I had both codes and have felt a real difference with the ride. Haven't had any issues yet.
How long have you had the new cats?

Rock has 4 which did you buy?
Davico?
Eastern Catalytic?
Walker?
Bosal?
 

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2007 6 speed manual tarnished platinum
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Re: How many Catalytic convertors replaced on this forum?

Both of mine replaced, I just bit the bullet and bought GM. Not hard to do yourself.
 

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2003 cadillac CTS 3.2L
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Please help me!! Me and my dad bought a 2003 3.2l cts and it had all sorts of problems. We replaced the cpu recently because we had a problem with p0160 and it worked, however now, we have another problem and that is p0496. We replaced the purge canister selenoid and drove it for awhile, light came back on! Hooked the obd2 reader up and now it comes p0496 and p0420! Could i possibly have did something to a o2 to do this? Guess you could say i got kinda mad at a stripped torx head bolt and had to move wires to try to remove the bolt with a chisel
 

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2003 cadillac CTS 3.2L
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AND also. Can anyone explain the four hoses running into two holes on the top? My second hose from the left is not connected to anything!
 
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