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Catalytic Converter

by crypticlineage, January 23, 2007

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Code: P0420 (bank 1)

More than likely, cat is bad, because O2 sensor on bank 1 was replaced less than 8k miles ago.

My mechanic referred me to a muffler shop and the dude quoted me $275 including installation, the cat will be new and has a 5 year, 80k mile warranty. He said the regular price is $329 but he'll give me referral price.

Does this all sound good? I am guessing this is going to be a direct fit cat but not a Toyota OEM part.

For that price - you could probably get an OEM direct fit cat - online. I'd shop around for some more quotes and see what they ballpark in your area. When they changed the last O2 sensor - was it the upstream or downstream one - I assume Bank 1 is the upstream or before cat (usual convention). This code can also be tripped by the downstream O2 sensor or even a bad ECT sensor - I would have a shop backprobe the rear sensor and see if it is working correctly or not, before I start slinging money around on swapping parts. Just because the OBD-II code is set and says this X sensor or part is bad - doesn't always mean that is the culprit - the mechanic has to do some diagnostic work instead of saying the code is X = this X part automatically bad.

Here is my rationale:

1. If I get diagnostics done (backprobing the rear sensor), I still pay at least one hour labor ($85), plus then I either replace the oxygen sensor ($150 for each sensor plus the labor), so I am down by $300. Then I find out that the cat is bad as well, which means another $300. Altogether $600 or more.

I must have poured 20-30 gallons of 10W30 oil in my old engine and all that smoke went through this cat so it is highly likely that it is shot. I have experienced gradual decline in "acceleration power" during all this time which could be an indication of cat slowly getting poisoned.

Fish: Can you post some links to online retailers for OEM cats?

Yeah, you're probably right about the cat. Since you had a terrible time with heavy oil consumption - all those additives could have killed the catalytic converter. As for online retailers - I would try www.1sttoyotaparts.com (probably be pretty expensive), www.rockauto.com (lots of bodyshop use them), and then start looking at aftermarket. There has been a few posts here on the forum that make mention of some universal converters at Summit Racing - they would probably have the best prices around for aftermarket due to the volume of business they do.

Thanks fish. Can someone explain to me the difference between aftermarket and OEM? Does aftermarket mean that the part has been manufactured by an independent business to the specifications of Toyota? And OEM is actually made under Toyota banner and sold through Toyota?

Bikeman982

Thanks fish. Can someone explain to me the difference between aftermarket and OEM? Does aftermarket mean that the part has been manufactured by an independent business to the specifications of Toyota? And OEM is actually made under Toyota banner and sold through Toyota?
I believe you have it correct. Aftermarket means the part is made to replace the original, although made by someone else.

 

Sometimes they are better, other times not as good.

The OEM means original equipment manufacture, or same or equivalent to what came on the car.

links dont work, probably aftermarket tho.

Bikeman982

Are following cats aftermarket or OEM? I couldn't tell.

 

<a href="http://www.pitstopautoparts.com/catalog/buy.php?make_text=toyota&model_text=corolla&ml=cor-910-001&year=2000&part_name=catalytic_converter&brand_name=dec&make_code=TO"> DEC Catalytic Converter</a>

A-B-Parts Catalytic Converter

Edit: I cannot figure out how to post a link here.

The way I post a link is to go to the web page, right click on it and copy, then go back to your post, right click and paste.

 

 

Well finally took the plunge and replaced the cat with an aftermarket one, don't know what brand it is. But it has 5 year, 80k mile warranty on it. Total cost: $275 including taxes. Immediately noticed improved acceleration. The old cat was definitely clogged.

Should I clear the code (I only have P0420) or wait for it to disappear by itself?

Hopefully this would be the end of the great scamming saga I have been boring you guys with for over an year now.

Things replaced at mileage 116,500:

2001 Engine 1ZZFE $1582.00

Iridium Denso Spark Plugs $48.00

PCV Valve $5.00

OEM Filter $5.00

Shell 5W30 motor oil $8.95

OEM Air Filter $19.00

Catalytic Converter $275.00

Valvoline Dexron III / Mercon ATF 1 quart $4.00

---------------------------------------------------

Total invested: 1946.95

Peace!

Bikeman982

Well finally took the plunge and replaced the cat with an aftermarket one, don't know what brand it is. But it has 5 year, 80k mile warranty on it. Total cost: $275 including taxes. Immediately noticed improved acceleration. The old cat was definitely clogged.

Should I clear the code (I only have P0420) or wait for it to disappear by itself?

Hopefully this would be the end of the great scamming saga I have been boring you guys with for over an year now.

Things replaced at mileage 116,500:

2001 Engine 1ZZFE $1582.00

Iridium Denso Spark Plugs $48.00

PCV Valve $5.00

OEM Filter $5.00

Shell 5W30 motor oil $8.95

OEM Air Filter $19.00

Catalytic Converter $275.00

Valvoline Dexron III / Mercon ATF 1 quart $4.00

---------------------------------------------------

Total invested: 1946.95

Peace!

May you enjoy many more miles on your car!!

 

 

Code will clear itself after some time has passed - but it would be a good idea to clear all the codes and start "fresh" in a sense - no old codes stored to confuse diagnostics in the future. I with Bike on this - I believe many remembered your incredible ordeal with the car - hopefully this will resolve many of the issues you had previously and now be trouble-free.

I agree, clear the codes... some codes may take a long time before they self clear... glad to hear it's running good! Hopefully I'll have the last of my codes cleared up by next week and be in the same (not leaking) boat as you.

Thanks fish and bike.

Update: When I cleared the code, the pending P0420 had already disappeared. I have driven 300+ miles after clearing the codes and none have come back. Car is running smooth, engine sounds and performs fine, doesn't burn a drop of oil, no smoke through exhaust and the tranny fluid level is constant.

Big smile on my face! default_smile

O.K. all, now it is my turn to suffer! default_sad

My check engine light came on, I brought it to my mechanic, he hooked up the scanner. At first he thought it was a vacuum leak and tightened something, but the check engine light came back on later that night. I brought the car back the next day and after looking for the leak and hooking up the scan, he thought it was the upstream oxygen sensor. He installed the new sensor but it ran worse than with the original sensor. He reinstalled the original and I'm running with the light on now.

I ran into a mechanic in a parking lot who suggested that it might be the catalytic converter. When I mentioned this to my mechanic, he stated if the cat was going, the code would have come up on the scan. I'm not burning oil.

Any suggestions? Help! default_sad

Sorry All, my code is not the infamous P0420, but P0171. I am running lean on the air/ fuel ratio mixture on one engine bank (whatever that means). Thanks to my local Auto Zone, the probable causes are 1. If one and two codes set together suspect fuel pressure or MAF sensor, 2. Oxygen sensor defective, 3. Ignition misfire-repair or 4. Fuel injector problem. My mechanic cleaned the MAF and he tried replacing the upstream sensor to no avail.

About 90% of the time - cleaning the MAF will fix the P0171 code. This assumes that the MAF is working correctly. Check out this recent post on the forum - I list the expected values from a MAF sensor on an 8th gen Corolla.

https://www.corolland.com/forums/index.php?...st&p=153508

I'd check with the mechanic and see if the plugs look OK - replace if in doubt. Double check the plug gap - should be 0.043" to 0.044" gap. Make sure all the injectors are firing - a quick check is to use an automotive stethoscope and listening to each one "click". I'd also check for intake leaks - around the air box, tubing running to the throttle body, leak in the hose connections around there, leak on the intake manifold itelf, etc.

About 90% of the time - cleaning the MAF will fix the P0171 code. This assumes that the MAF is working correctly. Check out this recent post on the forum - I list the expected values from a MAF sensor on an 8th gen Corolla.https://www.corolland.com/forums/index.php?...st&p=153508

 

I'd check with the mechanic and see if the plugs look OK - replace if in doubt. Double check the plug gap - should be 0.043" to 0.044" gap. Make sure all the injectors are firing - a quick check is to use an automotive stethoscope and listening to each one "click". I'd also check for intake leaks - around the air box, tubing running to the throttle body, leak in the hose connections around there, leak on the intake manifold itelf, etc.

Thanks again Fish. I just had the plugs replaced about 5K miles ago, but I'll ask him to check. I'll give him your information and hope for the best.

Since you had a terrible time with heavy oil consumption - all those additives could have killed the catalytic converter.

You know I really wonder if this isnt where my mileage problems started after doses of seafoam and b12 to clean the crankcase around 16k miles apart. Would autorx be easier on the cat converter than these?

You know I really wonder if this isnt where my mileage problems started after doses of seafoam and b12 to clean the crankcase around 16k miles apart. Would autorx be easier on the cat converter than these?
Be about the same - AutoRx is chemically some sort of fatty acid / lanolin ester. Though, this will only be introduced to the cat if burned by an oil consumption mechanism. Otherwise it will stay in the crankcase. Seafoam and B12 - depends on how it was added, into fuel system, intake system, crankcase, etc. Might actually have a case where the solvents have cleaned too well - could have exposed a leak in the induction system - causing some mileage issues. Hard to say for sure without more diagnostic work.

 

 

The seafoam and b12 were added thru the tank and crankcase. I still have a slight film of varnish at the top of the engine near the oil filler that scrapes off easily by finger nail but down inside looks cleaner from what little I can see thru the hole. The oil sure stays much clearer afterwards so I have no reason to believe the varnish is down below, just up at the very top.

Hey guys, back to my cel and the P171 code, sorry. Cudos to my mechanic; he has checked the following: upstream oxygen sensor, plugs, smoke test on intake, fuel pressure, checked the injectors, cleaned and tested the MAF, and gave me a scanner recorder to read and analyze the data; all at no cost to me! All came up good; the cel is still on. Does anyone have any further suggestions to this mystery?

If all that stuff checked out within spec - you could be chasing a sensor ghost in the ECM. Sometimes a ECM will get into a funky mode when sensors are reporting back within a certain threshold. Sometimes they will trigger a CEL, sometimes they won't. On the 8th gen Corollas - a false EVAP code was pretty common, 9th gen had similar woes - usually they were fixed with an ECM update. P0171 is usually MAF related on cars with MAF sensors - could also be a wiring issue (intermittent ground) that is causing the ECM to freak out.

If the mechanic didnt clean the maf with maf cleaner then that could be the problem. I have seen it posted that the electric cleaners can leave a film that you cant see which can cause problems even though it looks clean. People have had problems with cleaners that have silicone it in too. The problems cleared up once maf cleaner was used.

Like fish said reset the ecm, and get the mechanic to clean the maf again with maf cleaner because sometimes people have had to clean the maf a couple times before it worked properly anyway since the cel came back after the first cleaning.

Bikeman982

Reset the CEL and see if it comes back on.

If it does, problem still exists.

Re-check everything associated with the system and change, if in doubt.



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