GenVibe - Community for Pontiac Vibe Enthusiasts

I brought my 2003 Vibe to Advance Auto because the check engine light is on. The result was:DTC (Codes)PO420Catalyst EfficiencyBelow Threshold (Bank 1)Does anyone have any ideas?

My run in with P0420 is mentioned in http://forums.genvibe.com/zerothread?id=19728how many miles on your car?

110,000 miles

darn joatmon, you beat me to it .... I was gonna post the same link...The P0420 code usually refers to a bad Catalytic converter or Oxygen sensors.

There seem to be no driveability issues, noises, or loud exhaust. Any ideas on a price for a cat? Also will it pass NYS inspection with this CEL on???

Quote, originally posted by reb »There seem to be no driveability issues, noises, or loud exhaust. Any ideas on a price for a cat? Also will it pass NYS inspection with this CEL on???if you go after market "flowmaster" about 50-80bucks "not installed" if you stay factory at the stealership GOD ONLY KNOWS lol.and to answer your last question. NO it will not pass with the CEL light. And if you think justing having them clear the code and taking it threw inspection just after clearing it, IT STILL WILL NOT PASS. It take about 100 miles for the computer to reset, and if you try and get threw inspection prior to that the emissions computer will still see that you just cleared codes and will win you an automatic fail.

I couldn't pass NY emissions with that code. My needed a cat, and it was covered up to 80K miles. I think it costs 400+.

my CEL just came on last week and he cleared it for me but it came on again tuesday so he said hell need to check it out to see if its one of the o2 sensors or the catalytic converter......i have about 91,000 miles on my vibe.....it goes in monday to get looked at

yep.....catalytic converter it is.....

time for a cat back magnaflow exhaust system... parts and shipping probably cheaper then the stock converter in parts alone.

i have a magnaflow cat back haha but that doesnt include the cat its just from that back......atleast thats what i thought.....kinda too late anyways because the cat is being installed tomorrow

Quote, originally posted by hskater26 »...the cat is being installed tomorrowhow much did that cost?i just passed 100k haven't had any o2/cat probs yet. (knock on wood)

htey said it would be 625 with the install but when i took it in today they called me back saying they ordered the wrong one and the right one will be 100$ cheaper so i guess itl be around 525 haha

I know it has been a while since this topic was discussed, buy I am having code 420 problems. I started getting them last fall and long story short, I replaced my catalytic converter with a Walker brand in December of '07. I have not had the code come up in 6 months. It recently came up, stayed up for a couple of weeks, cleared and came in again last night. I took it to my mechanic who said it was the same 420 code as last time. He chastised me for not buying a Toyota catalytic converter and said I get what I paid for. My feeling is that it is not the converter again, though I can't be sure. Does it sound plausible that it could be the converter? Is Walker that much less of a quality than Toyota? Why would my light have stayed off for 6 months if it was my O2 sensor? What should I do next, take it to the dealer? Please help, thanks.

Walker cats are good cats.Depending on what cat you bought the ultra or stock catalytic converterthe stock has a 5 year on structrual intergrity or 25,000milesthe ultra has a 50,000 mile warranty or 5year structrual.Find your repair order. My thoughts are you will have to pay labor but not for the new part

Quote, originally posted by robodog61 »I know it has been a while since this topic was discussed, buy I am having code 420 problems. I started getting them last fall and long story short, I replaced my catalytic converter with a Walker brand in December of '07. I have not had the code come up in 6 months. It recently came up, stayed up for a couple of weeks, cleared and came in again last night. I took it to my mechanic who said it was the same 420 code as last time. He chastised me for not buying a Toyota catalytic converter and said I get what I paid for. My feeling is that it is not the converter again, though I can't be sure. Does it sound plausible that it could be the converter? Is Walker that much less of a quality than Toyota? Why would my light have stayed off for 6 months if it was my O2 sensor? What should I do next, take it to the dealer? Please help, thanks. Have you ever had the O2 sensors replaced? Did you replace either of them before you did the cat? If not, please replace them BOTH, before you go and spend HUNDREDS on a cat... I'm sorry, this is going to sound harsh, but in the grand scheme of troubleshooting, the easiest and CHEAPEST parts should be replaced FIRST... If you had 420 codes it says cat below effiency, right, so why spend hundreds on a cat when a pair of o2 sensors is less than 150$...??? I think your machanic is a shister, that is unless you did the o2 sensors first, then my above statements mean nothing..

At 110k, the car needs tune up (before spending money on O2 or catalytic converter).My car gave the code p0420 at 159k miles. I replaced spark plugs, air filter and cleaned TB, PVC, IAC valve, MAF sensor. So far, after 500 miles the code doesn't come back yet (After tune up, gas mileage increases more than 2 mpg).

Quote, originally posted by b03matrix »At 110k, the car needs tune up (before spending money on O2 or catalytic converter).My car gave the code p0420 at 159k miles. I replaced spark plugs, air filter and cleaned TB, PVC, IAC valve, MAF sensor. So far, after 500 miles the code doesn't come back yet (After tune up, gas mileage increases more than 2 mpg).Agreed, but, at either of those milages, it would be a good idea to replace BOTH o2 sensors, it's the ONLY way the car actually knows how the motor is running.. I bet you'd pull at least a few more MPG by doing it to boot...

Quote, originally posted by Sublimewind »Agreed, but, at either of those milages, it would be a good idea to replace BOTH o2 sensors, it's the ONLY way the car actually knows how the motor is running.. I bet you'd pull at least a few more MPG by doing it to boot... Yes, you are right.

Based on what I have read here, I am going to replace both my O2 senors. Is that something that is easy to do yourself? Are they simply threaded on, remove and replace?Also, why did my light stay off for 6 months after I changed the catalyst if it really was the O2 sensors. If the O2 sensors were bad, why did the light not come on right away after changing the cat?

Quote, originally posted by robodog61 »Based on what I have read here, I am going to replace both my O2 senors. Is that something that is easy to do yourself? Are they simply threaded on, remove and replace?Also, why did my light stay off for 6 months after I changed the catalyst if it really was the O2 sensors. If the O2 sensors were bad, why did the light not come on right away after changing the cat?O2 sensors work by heating an element, if it's hot enough, it's usually fine.. I used to get P0420 codes on my Subaru all the time that would go away and come back periodically... A good mechanic friend of mine asked me about all the missing heatsheilds from my stock exhaust header (on a subaru it comes out of the bottom of the motor, and is mostly exposed to air passing under that car) I told him that they all rotted off.... He said it's very possible that I could be running the exhaust TO COOL, and that the cat was "going out" A cat runs at about 1500 degrees, once it lights off, or starts the reaction with the exhaust.. which takes a few minutes for it to get hot enough... Well, back to the question, if the sensors were failing and reading low, like the cat was cooler than usual, and then you replaced the cat. After you would have a nice hot, restriction fee cat (which is a very good thing, mind you) but still have failing O2 sensors, it would stand to reason that the o2 sensors have continued to foul or fail, over that period of time.. As far as replacing them, it shouldn't be that difficult, you do/may need a special tool, but it's something you can get for free at AutoZone through the "loan a tool" program...

Quote, originally posted by Sublimewind »Agreed, but, at either of those milages, it would be a good idea to replace BOTH o2 sensors, it's the ONLY way the car actually knows how the motor is running.. I bet you'd pull at least a few more MPG by doing it to boot... I second this... On this site it seems with this code many ignore it and do not replace the O2's. I do not understand this thinking. (This is not directed to anyone in this thread BTW...)The car is not supposed to throw codes and it if does it is telling you something.Throwing codes is not normal, did the car throw codes when new? No, and if it did it went to the dealer right? Even if the code disappears. Give a code one time to appear, after that, get it looked at and the O2 replaced. Do not replace a bad O2 and it will take out your cat eventually. Replace and cat and not the O2 and the same thing will happen. The O2's talk to each other on how the engine is running. The one monitors before the cat, the other after and if one is off, it will cause issues. Period, enough said!

Quote, originally posted by robodog61 »If the O2 sensors were bad, why did the light not come on right away after changing the cat?Probably because the old cat was getting clogged and the new one was new, and flowing better then the clogged old one. Just a matter of time before the O2's took out the new cat.

I ordered two new O2 sensors for about $250 total. I assume that replacing both is the way to go. Is that price seem about right? I am going to replace them tomorrow.

Is that for GM or Bosch sensors? Seems a little high to me but I have not bought any for the Vibe so I dunno...Honestly the last two I bought, I got a discount from a friend at a GM dealer. And right, I would replace both too at once. You do one and not the other and you may just be back doing the other at some point. So why not do both so you know where you are at with them and many trouble free years then.

After a quick search, the price you paid seems about right! Damn, I had no idea! That could be why many ignore the code as well. Two sensors installed at a garage and I do not even want to think of the bill!I even looked on ebay and there are Universal kinds! Garbage, people should run from those!

Thanks for the info. I don't know the brand name. They were ordered from a local parts store and he told me that the dealer would cost much more. One more question - did I damage my new cat by driving with faulty sensors? The parts guy said no and recommends what he calls a "cat cleaner" that you add to the gas tank. What do you think? Thanks

Yes the dealer would be more for sure. Nahhh, I agree with the parts guy and think you will be just fine with the cat!Now the cat cleaner I have never heard off. Maybe he meant an engine and fuel system cleaner?? If so, I recommend Chevron Techron. I have heard of a product called Zmax that "claims" to clean O2 sensors adding it to the fuel tank! Do not believe this! I even posted here an article link that states Zmax claims are unsubstantiated and Zmax is being sued.

I have just finished my sad saga on the check engine light. My original mechanic was right, the Walker Catalytic converter was no good. I had another mechanic do a detailed analysis with a nice computer program under various engine loads. It was consistently failing the cat efficiency test under load. At idle, it was fine, but failing under load. I went ahead a bought a new GM converter for around $500 (the Toyota one was about $1100). We will reperform the test later to prove that the cat is OK. The bottom line is that I paid about $350 for a Walker cat converter that only lasted 8 months. I didn't get any money back because GM was going to give me $80 for the old converter and the best I could hope for from the parts store was a new, inferior Walker converter so I took the $80. Both mechanics swore that anything other than OEM converters were no good and the auto parts store guy said that he has never heard of a problem like me and the Walker cats are good. I also did NOT replace the O2 sensors as the computer program says they were good. The replacements that I bought but never installed were STANDARD brand which the mechanic also said was junk. Oh well, live and learn.

just got this code again the other day.....already replaced my cat about a year ago when it came on.....guess ill try the O2 sensors

Did you use a Toyota or Pontiac catylic converter or an aftermarket? I had my mechanic do an fancy test and he told me the O2 sensors were good, it was the cat. I had the same experience, i.e., it was clear for about 6 months and then came back, but it was because of the Walker cat.

honestly i dont know what the mechanic used.....but its been about 6 months or so ill have to find the reciept

How do you clean an MAF without ruining it?