: Looks like my right side catalytic converter needs to be replaced (P0420)



M.A.C
10-28-10, 08:55 PM
It appears the right side (passenger side) catalytic converter needs to be replaced, which is part of the exhaust manifold. Just curious if anyone knows if I can replace it myself without need to lift the engine. It looks like I might be able to gain access to the manifold bolts through the wheel well? Otherwise, maybe from underneath.

mike sts
10-28-10, 09:03 PM
GM extended the warranty to 200,000 miles for the cats, someone on here posted the recall letter print it bring it to the dealer and get them done free

Bigdawg58
10-28-10, 09:55 PM
GM extended the warranty to 200,000 miles for the cats, someone on here posted the recall letter print it bring it to the dealer and get them done free

yupp GM should replace it call your local cadi dealer and get it scheduled for replacement.

rzambrano
10-28-10, 10:22 PM
It appears the right side (passenger side) catalytic converter needs to be replaced, which is part of the exhaust manifold. Just curious if anyone knows if I can replace it myself without need to lift the engine. It looks like I might be able to gain access to the manifold bolts through the wheel well? Otherwise, maybe from underneath.

Here you go.

http://picasaweb.google.com/cpuhack/Public#5530274974423643170

M.A.C
10-29-10, 07:41 PM
Thanks for the information. I called a Cadillac dealer and made an appointment where the techs will diagnose the problem and make sure it's the catalytic converter. Once confirmed, it will be replaced free of charge. My '05 STS-V8 has the P0420 code (Catalyst System Efficiency Below Threshold (Bank 1) with the MIL light on, which fits the criteria for the 200,000 miles extended warranty and replacement.

M.A.C
11-03-10, 06:31 PM
UPDATE: Took my car in today and was told that both catalytic converters need to be replaced. I knew the right side (bank 1) was defective and was suspicious that the left side was also close to the same. I'm glad both are going to be replaced since I plan on keeping my STS for the foreseeable future. GM's willingness to extend the warranty to 12 years or 200,000 miles couldn't have come at a better time.

Thank you GM!!

mywifekids1
11-03-10, 07:54 PM
Mac what area dealership in New Jersey do you go too for service.

caddyfat2
11-03-10, 08:17 PM
Thanks for the information. I called a Cadillac dealer and made an appointment where the techs will diagnose the problem and make sure it's the catalytic converter. Once confirmed, it will be replaced free of charge. My '05 STS-V8 has the P0420 code (Catalyst System Efficiency Below Threshold (Bank 1) with the MIL light on, which fits the criteria for the 200,000 miles extended warranty and replacement.
I have been getting a CEL light on also intermittingly. OnStar said it was a catalytic converter low efficiency threshold bank 2 so when I bring it in for my oil change I will let them diagnose and fix the problem.( Got the letter from GM last week.)

mike sts
11-03-10, 09:07 PM
whats the problem with the cats poor design have they fixed this flaw or are they replacing the high failure catswith the same design high failure cats

EChas3
11-03-10, 10:19 PM
The OEM supplier was probably cutting corners on the platinum. For a while, car strippers were just cutting the cats off cars!

M.A.C
11-14-10, 12:35 AM
Both catalytic converters have been replaced, which took all morning into the afternoon. My STS is a much different car now. Even the harsh shifting is going away. It seems like the PCM is recalibrating and shifts are getting smoother. This has been my experience so far but I will continue to monitor the situation. The power difference is also noticeable, as acceleration is much better with smoother shifts. The Cadillac dealership techs found both converters needed to be replaced because the Tech2 picked up codes for both and also there were loose catalytic parts in both converters. Some of the early '05 STS-V8 converters fall apart.

amgqmp1
11-14-10, 12:28 PM
Sounds like an excellent outcome! If you don't mind me asking, how many miles on your '05 STS V8 when you started getting CELs?


Both catalytic converters have been replaced, which took all morning into the afternoon. My STS is a much different car now. Even the harsh shifting is going away. It seems like the PCM is recalibrating and shifts are getting smoother. This has been my experience so far but I will continue to monitor the situation. The power difference is also noticeable, as acceleration is much better with smoother shifts. The Cadillac dealership techs found both converters needed to be replaced because the Tech2 picked up codes for both and also there were loose catalytic parts in both converters. Some of the early '05 STS-V8 converters fall apart.

M.A.C
11-14-10, 01:01 PM
Sounds like an excellent outcome! If you don't mind me asking, how many miles on your '05 STS V8 when you started getting CELs?

At about 152,000.

nguyendot
11-15-10, 09:49 AM
My 06 had the same problem at about 30,000 miles. The car was totally different - I lost about 1/3 of my power and it smelled horrible coming out the back.

Had them replace both cats under warranty and the power was back!

Dvargas2811
08-08-12, 06:35 PM
Here you go.

http://picasaweb.google.com/cpuhack/Public#5530274974423643170

Can you please send me the letter again, I am having the same issue and missed the 80000 mile warranty by 100 miles. This would save me $1400!

1BadCadSTS
08-08-12, 06:45 PM
Only applies to 05 STS v8

209ziggys
08-10-12, 02:46 AM
The good people at Cadillac replaced all three of my converters for free by honoring there 12year 200000 mile warranty on there converters

1BadCadSTS
08-10-12, 05:21 AM
No 05+ STS has 3 cats...

Charles Warren
08-29-12, 10:41 AM
my ses light comes on then goes off. it was 430 at first now it keeps saying 420, guess both of mine are gone too. and yes it feels sluggish and drinks gas now. will be going today or tomorrow morning.

rocksitcts
01-21-13, 11:56 PM
are you talking about any caddy ??? or just the sts ??? i have a cts 110,000 miles and the cat needs to be replaced code 0420 below threshold code any info ?

Bruins
01-22-13, 01:09 AM
So it only applies to the v8 for sure? I have an 05 STS v6 with 45000 miles and my cats are both throwing P0420 codes like crazy. Does anyone have a copy of that GM letter they can put back into circulation? The link above is dead.

1BadCadSTS
01-22-13, 09:07 AM
V8 only.

anniecathleen
01-23-13, 01:19 PM
I have a 2006 sts v8 and catalytic converter is toast. Engine light going on and off car runs like someone stuck a potato in the muffler. I do know that there was a recall on 2005 catalytic converters and I also know that the same converters were used on 2005-2007. Information I received from a parts manager at Cadillac. I am taking my car into the dealership on friday so I will keep you posted. I did see a post here that indicated they changed the warranty to 200,000 miles . I am not really to happy with my car. We have 88000 miles and have had to replace the ignition switch, power steering pump and now the tire moniter is going out. Really not feeling good...I know there are repairs to any cars but Geez!

Ludacrisvp
01-23-13, 02:28 PM
Some things are just part of taking care of a car. The TPMS "going out" is called you have a car that is 7 years old or close to it each wheel has a battery in the transmitter that eventually dies ... Batteries don't last forever, get over it. Just replace all 4 of them and be done with it. Go check out the cat and hopefully you can get it covered by the extended warranty, or see if the dealer will cover part of it or something, if not find an aftermarket cat for cheaper and replace it. I want to say that there have been steering issues reported for certain STS models that don't have the STS-V steering setup. Did you replace the ignition switch due to a failure or for the cosmetic annoyance of those known peeling paint / finish for the first switch used? Cars don't last forever without working on them.

curtc
01-23-13, 03:57 PM
find an aftermarket cat for cheaper and replace it.

Unfortunately there is no aftermarket cats available as they are built into the manifolds as one unit, that is what I was told by my local GM dealer. I have received the P0430 code as well a couple of times, I just erase it with my scanner and drive on...Haven't seen it for about 1,500m now, haven't noticed any performance issues either, car runs/drives just fine. I consulted my GM dealer about a possible goodwill replacement as I am at 94k, 14k out of the 8/80 emissions coverage, they said it would not be covered 100% but there's a chance it could be partially covered by GM. I informed them that I would contact them if the SES light returns.

Waiting for GM to extend the coverage for the cats on the 06+'s as they are the EXACT SAME! :) Won't hold my breath though...

Ludacrisvp
01-23-13, 04:23 PM
Unfortunately there is no aftermarket cats available as they are built into the manifolds as one unit, that is what I was told by my local GM dealer.
That is indeed unfortunate.