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Toyota Camry, Sedan
#18 of 153 2004 Toyota Camry 4Cyl Ck Eng Lt, P0420
Feb 27, 2009 (4:20 pm)
I am dealing with the exact same issue on my 04 Camry with 152k on the odometer. About a week ago the check engine light came on. I own a code reader which indicated that the upstream O2 sensor had failed. I went to the local autoparts store to purchase the sensor and was advised that I should replace both the upstream and downstream (below the converter) sensors at the same time.
The funny thing is the sensors were boxed as aftermarket Bosch, but actually the upstream was stamped "Toyota" and the downstream was stamped "Denso" which I believe both are OEM Toyota.
I went ahead and installed both sensors and the check engine light disappeared for about a day. The next day about halfway home from work (80 miles one way) the check engine light came on again, this time giving the code of P0420 which indicates the converter has failed.
I took the car to the dealer and asked them to check the new sensors to ensure that I had not recieved a bad sensor. The dealer did not bother to test them, and just assumed that they were good. He quoted $795.00 to replace the converter which he did not have in stock. I asked him how did he know that the converter was bad, and did he test the emissions from the tailpipe? He advised that he did not have the equipment to test the emissions and also admited that if the downstream sensor was bad it would indicate P0420.
My advice is to get the emissions from the tailpipe checked before you shell out for a converter, I know I am.
#19 of 153 Re: 2004 Toyota Camry 4Cyl Ck Eng Lt, P0420 [ab4d]
Mar 04, 2009 (5:23 pm)
First Id like to say I have fixed a lot of the po 420 codes on california and fedaral emission camrys 4 and 6 cyl. 9 out of 10 times it is from a failing cat. I have never ever seen a rear sensor cause a po 420 code. As a sensor fails It generally gets lazy not switching fast enough. On a car with a working cat the rear 02 sensor should look lazy and have very little activity at all, unlike like the frt air fuel sensor on a calif car, or an 02 sensor on a federal. If u have not noticed way to many waste money on the sensors because they have no clue what they are looking at It is very easy to diagnose this code if u have any clue what u are doing.The frt air fuel sensor can only be tested using a lab scope. Also aftermarket cats absolutely do not work on california emissions vehicles or they work for an extremely short time .On the later model camry 4cyl around 97 to 02? They have 2 cats one in the manifold and one in the frt pipe. If u are having the 420 code u could opt to try changing the front cat ( part of the frt manifold) As it is substantially cheaper then the rear. But both are monitored by the computer. I bet these people changing cats every 6 months are putting on junk aftermarket!!!!!!! The rear factory cat is around 1100 no way u are changing that every 6 months. And if the vehicle is running correctly easy to ck by cking fuel trims should last 100k or more. Please any questions u can e mail me.brad2500hdaol.com
#20 of 153 Re: 2004 Toyota Camry 4Cyl Ck Eng Lt, P0420 [toptech]
Mar 04, 2009 (8:19 pm)
I have a 2001 4cyl Camry 125kmiles and had the ck engine lt on and live in the northeast area. I went to autozone to ck the code and of course the P0420 popped up. Both sensors were replaced( 1 by the dealer at 90k miles and the 2nd by myself w/aftermarket sensor at 110k miles) I wasn't sure if it was the catalytic converter or not(maybe in denial cause it cost a lot to replace) but to make sure, I disconnected the battery overnite to reset the computer. The next morning, I connected it and the ck eng lite was gone and it hasn't come on ever since. The question is that is my catalytic converter bad or what? Did I do more damage by just resetting the computer or was it just an error? I assume if the cat was bad, the code would pop up. If I'm doing an injustice by resetting the computer tell me so, if not i guess nothing was wrong. I just hope i am not doing any damage.
#21 of 153 Re: 2004 Toyota Camry 4Cyl Ck Eng Lt, P0420 [tmoney4]
Mar 05, 2009 (4:19 pm)
Belive it or not it will be back on. If u had the code cleared it may stay out for several weeks or even a month Trust me it will be back. U will do no more damage to ur car if u clear it everytime it comes back on. But in most states it it has a code current ot in memory it will fail for an emissions sticker. I bet u have a cat that is borderline bad and under the rite circumstances ie load emgine temp fuel trims. The comp will pick up on it and trip the light again. Same thing happens when people replace an 02 sensor thinking they fix this problem and clear the code sometimes the light will stay out for a month til the computer sees the circomstances where the converter is not working the way it should it will put the light back on. Just ck back here when the light comes back on. The 420 code is an emissions code and it wont get u stuck or cause any problems but put the light on and maybe polute a bit more then it should in california standards.
#22 of 153 Re: 2004 Toyota Camry 4Cyl Ck Eng Lt, P0420 [toptech]
Mar 05, 2009 (8:08 pm)
Thanks for the info...i will definitly keep an i on it. Its funny u said that about the sensor. I replaced the downstream sensor9by the converter) and thought that was the problem and scared to take to the dealer cuz i no they r going to charge me an arm and a leg! lol If it goes on of course i will ck the code...if it is the converter approx how much is it from the dealer, i am in NY and dnt hav CA standards. I am a little handy...can i do it myself or is it too hard?Thanks again for the info
Mar 06, 2009 (7:19 pm)
It is Are u stitting down. The rear converter is aprox 1200. The front is aprox 400? Both are monitored by that rear 02 sensor. sometimes changing just front will do the trick. It sucks to change either as far as the cost. The labor is quite simple to change either. Metal gasket where the manifold bolts the head and ring gaskets at either end of frt pipe/converter assembly. Sometime the studs that are in the manifold can be a problem u may or may not need a torch. I know of no other fix other then factory cats as of yet. I am looking into one other alternative but am not sure of what the outcome would be.
#24 of 153 Re: [toptech]
Mar 08, 2009 (6:20 pm)
Thanks again 4 the info...I will definitly keep that in mind if I get the P04020 code and probably end up replacing either 1 or both cat. conv.
#25 of 153 Re: 2001 Toyota Camry 4Cyl Ck Eng Lt, P0420 [tmoney4]
Mar 09, 2009 (8:44 am)
I am having this exact same issue with my '01 camry 4cyl. Somehow I was lucky enough to purchase a "California" model in colorado...lucky me. I have just replaced the back cat 2 weeks ago, I figured it was going bad for a bit because it smelled extra rich and then the light came on. The guy I took it to replaced it for about $400. The light has been flirting on and off since then, I took it in last Friday and he tells me that this is a California model and that he had no idea and that this is the cat that is throwing the code. His quote is $600 for the cat plus labor. My question is, how the heck can you not notice that there is a cat on the exhaust manifold when you're under the car putting the rear cat on? At this point, I'm opting for a second opinion, but is it conceivable that someone could just not notice this? It sure doesn't look like a normal exhaust manifold to me.
My question is this; is this the cat that I should have worried about in the first place and the second one is just redundant since it's a California model? I live in colorado and I don't even have an emissions test to worry about, what I am concerned about is performance and possible ramifications down the road if I don't pony up to fix this in the next couple weeks? Will this cat going bad affect power because I have noticed as well these past couple of weeks that it is more sluggish tackling hills and I get a whiff of exhaust through the vents when it kicks up a gear.
Any help would be greatly appreciated. Also, I noticed one post asking how difficult this is to replace, if necessary, and I ask the same question since two sets of mechanics out here have missed the fact that this thing was even installed in the first place? Why throw good money after bad people?
thank you for your help, I greatly appreciate it after all I have been through with this car I really would like to do it the honor of driving it until it drops
#26 of 153 Re: 2001 Toyota Camry 4Cyl Ck Eng Lt, P0420 [grizz17]
Mar 09, 2009 (3:41 pm)
First question to u would be, Did that mechanic put on a factory cat from the dealer? I think I can even answer my own question And that is gona be a big no. It is roughly 1200 dollars for that rear cat from toyota. and if u use a aftermarket cat inplace of the factory, the light will be back on very shortly. On the california emission camrys Toyotas fix is to replace both cats. Sometimes putting on one new one will get u by for a period of time if the other is borderline. But i cant stress it enough that if u use aftermarket cats u will not get rid of this code and if it does it will be for such a short period of time if u got it for a 100 it would still not be worth it. The cat should not be making is smell rich U may have other problems causing ur car to run rich or lean that would cause damage to ur converter possible melting and u would notice power loss. To ck for a restricted converter u would need to ck the backpressure through the frt air fuel ratio sensor. And to see if ur fuel mixture is correct u would need to monitor ur fuel trim data with a scan tool. My best suggestion is to take it to someone that has had experience with this code on this model car. U may even want to concider taking it to a dealer.Even in colorado I would say u have a 50 50 chance of having a vehicle that has california emissions they are very common. The mechanic should have know it has 2 cats and should of know u dont use aftermarket on these california emisson cars. .If u did not have power related problems and a smell I would say drive it because generally the 420 code will not cause problems just polute a lil more then it should but in ur case where u notice it to be low on power I would have it looked at.Any other questions post here or e mail me I will give the best advice I can
#27 of 153 Re: 2001 Toyota Camry 4Cyl Ck Eng Lt, P0420 [grizz17]
Mar 09, 2009 (3:56 pm)
Hi Folks, Long time since I made my original post. I went through many cat converters before I got it right. Bottomline - be careful about aftermarket oxygen sensors. The dealers replaced the CATs but never even looked at the O2 sensors. When my mechanic changed it, it would not work well with the computer system in the Toyota, causing it to run rich, thus burning out 3 more CATs. (All replaced by my mechanic at no charge.) I finally took it to a dealer who knew how to fix the problem (3rd try). That was over a year ago and (knock wood) no problems since. I have had my Camry for about six years and the engine light was on for most of the first 4 years. Watch out for those O2 sensors. Good luck to all!!