Do I need a new Catalytic converter .....P0420
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bc21
- SSE Member

- Posts: 129
- Joined: Sun Jun 01, 2008 11:13 pm
- Year and Trim: Black 2000 SSEI and Red 2000 SSEI
- Location: Pittsburgh, PA
Do I need a new Catalytic converter .....P0420
I had code p0420 so I replaced the back O2 sensor. Code p0420 came back do i I need a new CAT. If so is there a good place to purchase one. If I recall years ago I had to replace the cat on my other SSEI but I had to get it from the dealer or try to order it from ebay do to the size of the pipe. Do you guys have any suggestions on a less expensive fix, trying to avoid the dealer.
BTW performance has not suffered and the cat is not clogged. Just the P0420 code keeps coming back.
Thanks for your time Brandon
BTW performance has not suffered and the cat is not clogged. Just the P0420 code keeps coming back.
Thanks for your time Brandon
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myfirstbonnie
- Resident Gearhead

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2015 Buick Enclave
2013 Buick Regal GS - Location: Hillsboro, Oregon
Re: Do I need a new Catalytic converter .....P0420
Is the cat the original? Sometimes you can bang on them and hear them rattle when bad. Most people buy a Magnaflowhigh flow cat and either install it themselves or have a local shop do it.
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bc21
- SSE Member

- Posts: 129
- Joined: Sun Jun 01, 2008 11:13 pm
- Year and Trim: Black 2000 SSEI and Red 2000 SSEI
- Location: Pittsburgh, PA
Re: Do I need a new Catalytic converter .....P0420
Thank you for your quick response.
It is the original CAT. Any suggestions on where to buy a Magna flow CAT? Should I go to Midas or monroe for this cat or do you have a better recommendation on a shop. (also can I buy the Magnaflow CAT online for a better deal) I am willing to spend the money for the right part. I just want the check engine light gone. Thanks
It is the original CAT. Any suggestions on where to buy a Magna flow CAT? Should I go to Midas or monroe for this cat or do you have a better recommendation on a shop. (also can I buy the Magnaflow CAT online for a better deal) I am willing to spend the money for the right part. I just want the check engine light gone. Thanks
- harofreak00
- Administrator

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- Year and Trim: 2004 GXP - plus a handful of other Bonnevilles
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Re: Do I need a new Catalytic converter .....P0420
Get a Magnaflow 99306HM on ebay.
Your original cat is worth $100-150 depending on the current cat prices, so don't just throw it away.
Your original cat is worth $100-150 depending on the current cat prices, so don't just throw it away.
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler
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bc21
- SSE Member

- Posts: 129
- Joined: Sun Jun 01, 2008 11:13 pm
- Year and Trim: Black 2000 SSEI and Red 2000 SSEI
- Location: Pittsburgh, PA
Re: Do I need a new Catalytic converter .....P0420
Haro thank you for the info. (I am assuming you are referring to scrapping the old one for the metal that is inside... thats what makes the old one worth $100).
Do you know if this is a common fix for the p0420 code? (i already replaced the rear o2 sensor)
Do you know if this is a common fix for the p0420 code? (i already replaced the rear o2 sensor)
- harofreak00
- Administrator

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- Year and Trim: 2004 GXP - plus a handful of other Bonnevilles
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Re: Do I need a new Catalytic converter .....P0420
Yes a bad cat loves to throw the P0420
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler
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TheMannn
- SLE Member

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- Joined: Wed May 02, 2012 10:52 am
- Year and Trim: 2001 Pontiac Bonneville SLE
Re: Do I need a new Catalytic converter .....P0420
I just installed a Magnaflow 24204 Direct Fit Catalytic Converter i purchased off amazon on my 2001 SLE. It was a simple job. The only trouble i ran into was, you need to get a pipe expander and slightly open the exit end of the converter a little. Just giving everone a heads up.
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bc21
- SSE Member

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- Year and Trim: Black 2000 SSEI and Red 2000 SSEI
- Location: Pittsburgh, PA
Re: Do I need a new Catalytic converter .....P0420
Awesome thank you
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DaMaroon
- SSEi Member

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Re: Do I need a new Catalytic converter .....P0420
Was curious for future
http://www.amazon.com/Magnaflow-24204-C ... flow+24204
Then saw
http://www.amazon.com/Walker-16386-Dire ... sbs_auto_1
It has: the core cost of $8.00 has been added to the total price
Who buys them for $100?
http://www.amazon.com/Magnaflow-24204-C ... flow+24204
Then saw
http://www.amazon.com/Walker-16386-Dire ... sbs_auto_1
It has: the core cost of $8.00 has been added to the total price
Who buys them for $100?
- harofreak00
- Administrator

- Posts: 26022
- Joined: Mon May 19, 2008 6:04 pm
- Year and Trim: 2004 GXP - plus a handful of other Bonnevilles
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Re: Do I need a new Catalytic converter .....P0420
Any decent scrap metal yard.
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

