P0420- Catalytic Converter - Bank 1 - Subaru Outback

sk8tr4lf1989 · 05-23-2011, 11:59 AM

I got this reading at advanced auto and then called my mechanic and told me the code is pretty straight forward and that is the problem. He said O2 sensors would throw there own code and some may say that there going bad but you'll only end up with the same code in the end. I was going to do the 5 minute fix with the spark plug thing.

I was also looking online at this part, is this something I could do myself or give to a muffler shop to put in? Thoughts and inputs please!

Thanks!!

2002 Subaru Outback Catalytic Converter - Bosal W0133-1842851

CNY_Dave · 05-23-2011, 01:06 PM

I am all for cheating IF you check everything and cannot fix it.

A vacuum leak can cause this, and since that can cause other problems it's worth checking for.

Also, an exhaust leak even after the converter can cause this code.

Dave

**AWDFTW** · 05-23-2011, 01:16 PM

I think your mechanic is wrong and whaty he told you is exactly the opposite of reality with our cars (I'm assuming you have an Outback. Year? Miles?)

P0420 is VERY RARELY a failing cat.

It is most commonly a failing oxygen sensor (front Subaru, rear any brand), vacuum leak, exhaust leak or what not.

Search that code on the forums and you'll find plenty of info.

Cats rarely fail without serious mechanical problems, I think your mechanic wants to give you an expensive repair bill.

sk8tr4lf1989 · 05-23-2011, 01:21 PM

It's a 2002 subaru outback sedan 3.0.
126,000 Miles

From what I've been reading replacing the O2 Sensors usually just results in the P0420 code coming back on at a later time.

I don't think he's trying to take me for a ride he's helped me out a lot for free.

I will def check everything over for leaks and all.

In PA do they actually read the rear exhaust or do they just go off of the computer they plug into it.

I was also reading that my car year is known to be over sensative with it's readings. That normally nothing is to wrong for it to throw that code, so that's why if there are no leaks I'm going to just do the quick fix.

CNY_Dave · 05-23-2011, 01:25 PM

Pffft, it'sa a baby. Up near 160k on my '03 H6, only code thrown was for the TPS.

Dave

sk8tr4lf1989 · 05-23-2011, 04:14 PM

Can anyone answer those questions please?

CNY_Dave · 05-23-2011, 04:18 PM

Do you mean, if you could install that cat yourself?

Those bolts can be difficult- but that is a 4cyl cat. Won't fit, I believe.

Dave

wilsonhp · 05-24-2011, 01:08 PM

I agree. Mine will roll over 200K miles later today. I'm now half way to 400K !!!

Only code I've ever had in mine was also for the TPS.

Quote:

Originally Posted by CNY_Dave

Pffft, it'sa a baby. Up near 160k on my '03 H6, only code thrown was for the TPS.

Dave

05-23-2011, 11:59 AM	#1 (permalink)
sk8tr4lf1989 Registered User Join Date: May 2011 Posts: 3 Feedback Score: 0 reviews	P0420- Catalytic Converter - Bank 1 I got this reading at advanced auto and then called my mechanic and told me the code is pretty straight forward and that is the problem. He said O2 sensors would throw there own code and some may say that there going bad but you'll only end up with the same code in the end. I was going to do the 5 minute fix with the spark plug thing. I was also looking online at this part, is this something I could do myself or give to a muffler shop to put in? Thoughts and inputs please! Thanks!! 2002 Subaru Outback Catalytic Converter - Bosal W0133-1842851

05-23-2011, 01:16 PM	#3 (permalink)
AWDFTW Super Moderator Join Date: May 2007 Location: Displaced to Chicago. Car: 2003 2.5 4EAT with AWP. Posts: 6,084 Feedback Score: 0 reviews	I think your mechanic is wrong and whaty he told you is exactly the opposite of reality with our cars (I'm assuming you have an Outback. Year? Miles?) P0420 is VERY RARELY a failing cat. It is most commonly a failing oxygen sensor (front Subaru, rear any brand), vacuum leak, exhaust leak or what not. Search that code on the forums and you'll find plenty of info. Cats rarely fail without serious mechanical problems, I think your mechanic wants to give you an expensive repair bill. __________________ 2003 Outback: "Kaylee". 128,000 and counting. Mods: GE Nighthawk low beams, HIR1 9011 high beam upgrade, Nokya 25k yellow fog lights, Fumoto valve, 04 Forester XT shift knob. Basics: G-Oil Bio-based Advanced Full Synthetic 5w30, Purolater oil filter, STP air filter, Valvoline Maxlife Dex/Merc ATF, Valvoline Durablend 80w90, Michelin Primacy MXV4. Also: More rust and parking lot scars than I care to think about.

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05-23-2011, 01:06 PM	#2 (permalink)
CNY_Dave Registered User Join Date: Nov 2007 Location: central NY USA Car: 2003 LLBean H6 Outback Posts: 3,428 Feedback Score: 0 reviews	I am all for cheating IF you check everything and cannot fix it. A vacuum leak can cause this, and since that can cause other problems it's worth checking for. Also, an exhaust leak even after the converter can cause this code. Dave

05-23-2011, 01:21 PM	#4 (permalink)
sk8tr4lf1989 Registered User Join Date: May 2011 Posts: 3 Feedback Score: 0 reviews	It's a 2002 subaru outback sedan 3.0. 126,000 Miles From what I've been reading replacing the O2 Sensors usually just results in the P0420 code coming back on at a later time. I don't think he's trying to take me for a ride he's helped me out a lot for free. I will def check everything over for leaks and all. In PA do they actually read the rear exhaust or do they just go off of the computer they plug into it. I was also reading that my car year is known to be over sensative with it's readings. That normally nothing is to wrong for it to throw that code, so that's why if there are no leaks I'm going to just do the quick fix.

05-23-2011, 01:25 PM	#5 (permalink)
CNY_Dave Registered User Join Date: Nov 2007 Location: central NY USA Car: 2003 LLBean H6 Outback Posts: 3,428 Feedback Score: 0 reviews	Pffft, it'sa a baby. Up near 160k on my '03 H6, only code thrown was for the TPS. Dave

05-23-2011, 04:14 PM	#6 (permalink)
sk8tr4lf1989 Registered User Join Date: May 2011 Posts: 3 Feedback Score: 0 reviews	Can anyone answer those questions please?

05-23-2011, 04:18 PM	#7 (permalink)
CNY_Dave Registered User Join Date: Nov 2007 Location: central NY USA Car: 2003 LLBean H6 Outback Posts: 3,428 Feedback Score: 0 reviews	Do you mean, if you could install that cat yourself? Those bolts can be difficult- but that is a 4cyl cat. Won't fit, I believe. Dave

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