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Car is throwing a bad cat code is there anything I can do without replacing the cats thanks
Sure if you really want to...buy spark non foulers and put 2 on each REAR o2 sensor. Code will disappear.

THIS WORKS ON NEARLY EVERY VEHICLE.

I was an emissions inspector I know all types of ways to defeat the light. BUT you do need to get the cats replaced at some point. This won't solve your problem

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2009 CTS 3.6L DI rebuilt to FE3 J55 G80 3.42:1
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Car is throwing a bad cat code is there anything I can do without replacing the cats thanks
It is possible, even likely, you have a marginal O2 sensor. It may well be the front one which affects mixture and driveability, vs. the rear "monitor" sensor. Can't say for sure without some diagnosis. Plot the front and rear sensor for the offending side, here is my experience with this issue. It's also possible you have a bad cat, but definitely look at the O2 sensors first. Cats typically last longer than O2 sensors.

If you have high mileage on the car, you should probably replace the front sensors at least just as regular maintenance. Improvements in fuel economy and driveability are the usual results.

Edit: if you have other engine problems causing misfires like ignition or bad timing chains, those can cause problems as well. The above advice assumes a good-running engine, perhaps not a valid assumption on a high-mileage car.
 

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Sure if you really want to...buy spark non foulers and put 2 on each REAR o2 sensor. Code will disappear.

THIS WORKS ON NEARLY EVERY VEHICLE.

I was an emissions inspector I know all types of ways to defeat the light. BUT you do need to get the cats replaced at some point. This won't solve your problem
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just to clarify, are you suggesting that the OP do something to skirt or somehow get around Federal emissions standards?
 

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8 No just to clarify federal emissions is not regulated where I live anyway .emissions is not part of inspection.
likewise, I live in a Texas county that doesn't require emissions testing, but what about the OP who lives in Penn? Just to clarify, does he have emissions testing in Albrightsville, PA?
 

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just to clarify, are you suggesting that the OP do something to skirt or somehow get around Federal emissions standards?
Nope. I gave info on where my background knowledge is from. He asked a simple question I gave a simple answer. I'm sure he is trying to turn off his mil light on his "off road vehicle" because it is annoying........

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Discussion Starter · #8 ·
Car
It is possible, even likely, you have a marginal O2 sensor. It may well be the front one which affects mixture and driveability, vs. the rear "monitor" sensor. Can't say for sure without some diagnosis. Plot the front and rear sensor for the offending side, here is my experience with this issue. It's also possible you have a bad cat, but definitely look at the O2 sensors first. Cats typically last longer than O2 sensors.

If you have high mileage on the car, you should probably replace the front sensors at least just as regular maintenance. Improvements in fuel economy and driveability are the usual results.

Edit: if you have other engine problems causing misfires like ignition or bad timing chains, those can cause problems as well. The above advice assumes a good-running engine, perhaps not a valid assumption on a high-mileage car.
Thank you . Car has around 120000 timing was done at 71000. I bought it pretty cheap knowing I would have to drop acouple into it . It was running like crap. I went through an found out it had copper plugs an 3 different brands of coils in it . I changed them out with acdelco iridum per plugs an a set of Bosch coils . Car runs alot better but still throwing a 0420 an the other 0430 I think .also I changed the purge valve.
 

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Discussion Starter · #13 ·
Brake/Break
Sorry thought I was here looking for help with my car not corrections with my grammar Apparently looking for help in the wrong place cause all it seems like to me is you like to pick apart every little punctuation an grammar error have at it thanks for the help no periods on purpose my new forum name
 

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2014 CTS4 Sport Wagon*Luxury 2016 CTS V-Sport Premium
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no one was questioning your grammar but only pointing out your spelling as that seems to be an issue with postings these days...and he is a moderator you know, that's kinda within his wheelhouse for keeping order here...don't take it personally...

several people chimed in with help for you and this Forum is indeed a very helpful Forum (I am also on the Gen 3 V-Sport Forum and there is little to no response to anything there lately)

stick around you'll find a lot on this Forum to be thankful for...especially on Thanksgiving

Bill
 

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Sorry thought I was here looking for help with my car not corrections with my grammar Apparently looking for help in the wrong place cause all it seems like to me is you like to pick apart every little punctuation an grammar error have at it thanks for the help no periods on purpose my new forum name
Apologies if you were deeply hurt by me pointing out a homophone in your post-- there was no 'picking apart' of anything. On a words-based format such as a help forum, this can be very critical and you will find that the effort you put into creating a clear and concise post will be rewarded with clear and concise responses.

Best of luck with your repairs.
 

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Sorry thought I was here looking for help with my car not corrections with my grammar Apparently looking for help in the wrong place cause all it seems like to me is you like to pick apart every little punctuation an grammar error have at it thanks for the help no periods on purpose my new forum name
You ask for help on a forum and you get what you get. Them's the brakes.
 

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Lol.
 

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Sorry thought I was here looking for help with my car not corrections with my grammar Apparently looking for help in the wrong place cause all it seems like to me is you like to pick apart every little punctuation an grammar error have at it thanks for the help no periods on purpose my new forum name
coming to a forum with a bunch of dedicated gearheads can be very helpful. However, these same gearheads aren't going to coddle you and they have strong opinions about almost everything. Grow a thicker skin and roll with the punches. That's what I did 7 years ago.
 

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coming to a forum with a bunch of dedicated gearheads can be very helpful. However, these same gearheads aren't going to coddle you and they have strong opinions about almost everything. Grow a thicker skin and roll with the punches. That's what I did 7 years ago.
Unless of course your name is AmbersAuto. Never saw this forum so "sweet". I laughed behind the scenes everyday I followed the progress. If you're a dude, forget about it (Robert De Niro style).
 

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Back to the problem at hand...

These cars can start to throw cat codes as the mileage gets up there. Unfortunately, the codes don't tell us if the sensors are failing or the cat is losing efficiency. If the upstream sensors have not been changed at 120k miles, they are likely at least part of the problem as they're getting really old at this point and have been exposed to lots and lots of exhaust gasses over their life to date.

This forum is full of threads about these sensors and the upshot is that you replace these in pairs (side to side) and stick with OEM. If after swapping in four new sensors, the voltage patterns of the upstream and downstream sensors don't fall into the correct pattern, then we're most likely looking at cat failures - which would be a shame but it does happen even at mileage as low as 120k miles.

My CTS 3.6DI has almost 160k miles on its odo and I had the cat codes. I monitored the voltage signals of the sensors and swapped out all four O2 sensors - I haven't seen the codes in months. I have used top tier gasoline exclusively for some years now and use Chevron Techron a couple of times a year as well.
 
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