p0420 CEL code - bad catalytic converter... questions...

[wallyuwl]

So I had two CEL codes checked out a month ago. One was for what was likely a bad MAF sensor, so I replaced that. The other they didn't tell me about really. A week ago the CEL comes on again, and this time I had my own reader. It is p0420, apparently a bad catlytic converter (vehicle is about 120k miles). I found a direct fit converter from Rock Auto for under $300. 5 yr, 50k mile warranty. From what I've found on the internet direct fit cats are pretty easy to install. Repair shops want $600+, and those might even be for universal fit. So I'd like to do it myself if it is pretty easy.My main question is: is it easy to do on a Vibe? My biggest worry is getting all the bolts apart. I don't have a torch. Also, my other main worry is if I need to replace any bolts (if the originals break or something during the process). Anyone know what size and quantity bolts, washers, etc. I should buy ahead of time to have on hand?Thanks.

[bassplayaz06]

this car has 2 cats. they're both in a middle section of pipe with the resonator. 2 bolts on each end gets it off. they shouldnt be too difficult to remove. i took mine off for the first time since the car was new, and all i needed was a breaker bar. strangely, all the bolts in the exhaust are standard, not metric.

[wallyuwl]

Thanks bass. Before making this thread I searched the forum for the code. Seems a lot of people (including bass) have replaced their cats. My question to you guys: what did you replace it with if you did it yourself? OEM? Or if aftermarket, what one? How has it held up?I'm looking at one made by Eastern, has a 5y/50k warranty and is half the price of the OEM part from gmpartsdirect (after you consider shipping and sending the core back). I think I'm going to clear the code (though it will come back), then in summer make a day of working on the car: cat, both O2 sensors, blower motor and resistor, oil change. Might need to do the oil change before then though.

[bassplayaz06]

i haven't replaced my cats yet. i might need to. i'm trying to fool the ECU and O2 sensors with spark plug anti-foulers.

[Salsa Guy]

There are plenty of good aftermarket CATs you won't need to fool the O2 on. Don't mess with the PRE-CAT just a goo quailty aftermarket about $300 and you should be able to fin a muffler shop to install for $100. The main thing is you need the O2 bung hole after the CAT. You could try and replace the O2 but it's not likely to be the issue.

[bassplayaz06]

my problem is i have no money. a $5 trick is all i can afford. i have to get the car inspected this month and it has to be a quick fix. they do the sniff check and everything here.

[bikejon]

Did this clear the CEL?

[silverbullet]

Funny that this got bumped today. This code just showed up for me over the weekend. I will be getting a small welder sometime this week and spend sometime practicing with it before I order the replacement magnaflow high flow cat I will be using. Good price and has great regiews. Many others seem to have complaints of failures within weeks of install.

[Raven]

PO420 is the most common code which comes up on pretty much any make of car. There are many causes for it to appear and only rarely is there anything wrong with the cat itself. A lot of people go out and spend a lot of money replacing a perfectly good cat only to have the code reappear in a couple of days or weeks. Some of the causes are a vaccum leak, bad intake manifold gasket or an exhaust leak upstream of the O2 sensors and cat. PO420 comes up on my daughters Outback once every month or two. I just read the code and reset it to turn off the light.

[DiveNut]

Hey silverbullet. I ended up going with a direct fit, Magnaflow piece (part #93200) on my 04 Vibe. Been 7 months and over 8,000 miles w/o a problem. If you do it yourself, be sure your have solid welds with no leaks or you'll throw a CEL again. Welding isn't my strong point so I had a muffler shop weld it in for $75.Pat

[silverbullet]

Thanks divenut, glad to know that fixed it for you. I really appreciate the part number, really want to make sure I get the right one for the car. I am working on getting the tools and parts together right now. might take a while tho, same old story, tight money. I have been wanting to learn some welding lately and this is just the perfect excuse to buy a welder and get to it. For less than I would pay to buy the entire cat assembly, or near the cost of having a shop weld the part; I can do it myself and get a welder out of the deal. I'll practice on some scrap pieces before I work on my own pipes. I have been looking into lots of welding info lately and I am confident with a little practice I can get the job done. There are two other reasons for doing it this way also. I am a pretty simple guy and one thing I love is tools, ha ha. So if I get a chance to add a new piece to the garage how can I say no? Not to mention learning a new piece of equipment can always pay off in the job field. The second reason I just was thinking of today, I have had the vibe for a couple years and it has not seen any shop, even for so much as an oil change, besides my own since I bought it. I think that's something I can take some pride in. Also I just seem to enjoy working on my vehicles. Lastly to raven, I am aware there could be other causes of the code, allthough I think this will be the fix in my case. I have considered the other causes and some I am comftorable ruling out because ofsome new parts brand new intake manifold gasket, o2sensor, etc... The only thing that I would be slightly worried about is a vacuum leak, just because it would be hard to find. But I believe it would have to be a large, likely noticable leak to cause this code. I disagree that this is rarely the solution, cats are essentially filter right? So they catch all the bad stuff and will eventually restrict flow, it is inevitable. They should plug up by design I would think. Besides all of that, worst case scenario is that I end up with an extra exhaust upgrade. Should match up nicely with my cat back system. Cheers

[silverbullet]

Divenut that part number seems to be the direct fit part, would be a little easier install but includes much more than just the converter. I was thinking of using a universal fit. Cut out the old cat and weld in this new one. http://www.autopartswarehouse....4xhPj

[DiveNut]

Quote, originally posted by silverbullet »Divenut that part number seems to be the direct fit part, would be a little easier install but includes much more than just the converter. I was thinking of using a universal fit. Cut out the old cat and weld in this new one. Yes, it bolts to the exhaust manifold flange and is welded to the existing downstream exhaust. I initially picked up the CAT only, like the one you are looking at, but there was not much material to weld the old flange to. I opted to return in and go for the direct fit piece. Didn't have the time to screw around cutting to old flange off the shot CAT, then having it welded to the new cat etc. The shop installed it in 20 minutes while my kids and I waited. But if you got the time, go for it.

[silverbullet]

Ok cool thank you. The flange does look a little tricky, but ill take that challenge. I got a welder set up today, I will practice on some scrap pipe tomorrow before I do welding on my own car. I will not be getting the replacement cat for a few weeks so I will practice when I can until then. I am no hurry, car drives fine as is. Thanks again for the info.

[Murdoc]

420 CEL has been an issue on my 2003 pontiac vibe for quite some time for me now. Inspection just came up and failed. Mechanic stated bad CAT and quoted me $728, which i declined. Mechanic said both O2 sensors are reading the same which means the cat isn't doing its job. After making call after call finally found someone to fix it for $250 (cheapest) im assuming they will cut and weld aftermarket one on. I'm also getting bad gas mileage so i will post results when i get this fixed hopefully by next tuesday.

[skimask]

Define "bad gas mileage".If it's really rotten, as in terrible compared to normal, I'd go out on a limb and guess you've got something else wrong, for instance a rotten injector/plug/etc.How long has the "light been on" and how many times did it flash while driving?

[joatmon]

Quote, originally posted by Murdoc »420 CEL has been an issue on my 2003 pontiac vibe for quite some time for me now. Inspection just came up and failed. Mechanic stated bad CAT and quoted me $728, which i declined. Mechanic said both O2 sensors are reading the same which means the cat isn't doing its job. After making call after call finally found someone to fix it for $250 (cheapest) im assuming they will cut and weld aftermarket one on. I'm also getting bad gas mileage so i will post results when i get this fixed hopefully by next tuesday.welcome to genvibe$250 is a good price. How many miles on your Vibe? My mpgs went up a few when I replaced my cat. That was at about 106K miles. Now it's up to ~260K miles, and I've been getting and resetting P0420 every other day, so I guess I need to get anotherI find that whenever I closely monitor mpgs, I drive more gently. It's also a good idea to average a couple of tanks' worth of mpgs to eliminate the normal fluctuations that occur from one tank to the next.

[Murdoc]

Sorry about the slow response, i have as of today 99,400 miles on it, i bought it when there was 39,000 on it. the CEL never was blinking its been solid for about 2 months until today. never really calculated gas mileage but its about a round trip of 25 miles to my work and back and with maybe a few local trips daily after work i use up nearly a 1/4 tank of gas the day after i fill up by the next day. just seems poor to me.Anyway i got the cat converter replaced today paid $256.52 it was a cut and weld job. Tomorrow it goes for state inspection again. Hopefully it passes. I drove it probably close to 100 miles today after the cat replacement and no check engine light yet!

[wallyuwl]

Be sure to get your intake manifold gasket changed, too, or you might be replacing that cat again sooner than later. The bad gasket has been suggested to be linked to the cats going bad. Make sure you get the newer reddish/rust colored one from a Toyota dealer. Several threads on here about the intake manifold gasket, including the part number and how to change it. A pretty easy job. Not a bad time to take off and totally clean out the throttle body, too, including the idle control valve inside of it (need to take off and replace the two "star" screws on the TB and you'll see it).

[Murdoc]

ive searched thru the forums but found no part number. anyone know what it is for that intake manifold gasket?

[sideshowalan]

Toyota part# 17171-22060Not a difficult job to replace, just take your time and pay attention to how all the plugs and hoses are attached while taking out the throttle body.

[Murdoc]

hopefully this is right throw this on and hopefully good to go for a long time!

[silverbullet]

Just got the last part I need to fix this ordered. 2 sensor bungs, One converter, some 2.5" tubing. One adapter and clamp will be the last thing. 2.5-2.25, will grab that from autozone. This will be part repair part upgraded exhaust.