Code P0420 - Catalyst efficiency below threshold

[PandaBear]

On a 97 Camry V6, bank one. On a car that has only 120k mostly local driving. The CEL comes on and then goes away, and the code is read after the CEL goes away.

Should I be worried and start throwing some simple parts to it? like O2 sensors, new plugs, wires, coils, exhaust gaskets, etc? Or just drive it till it comes up again or fail smog?

Would probably not replace the CAT unless it is the last resort. Cal emission cat is expensive.

 

[ARCOgraphite]

Does it run good otherwise or is it hesitating? Maybe it needs a good run on the highway? I've read in the past toyota had problem with a similar code on their Tacos and V8s tundra - IDR if it was really a weak 02 sniffer or a coilpack issue as the top two solutions for 90% affliction. Rmember if you have waste spark coilpack DONT run iridium plugs - try the new Denso TT or NGK DFE

to reduce misfire rate on the backward firing plug.

 

[hypervish]

Does your Camry have a 02 sensor after the catalytic converter? If so, that's the culprit.

But, it isn't necessary to replace. The P0420 won't effect efficiency or the way the car drives. It's purely for emissions.

 

[JC1]

My 98 Sienna has the same issue. I just reset the CEL everytime it comes on. I replaced the entire exhaust system from the front pipe to the back with a cheaper CAT and muffler and I think that's the culprit!

 

[Audios]

You can also do an O2 sensor spacer to pull it out of the stream.
Cheaper catalysts ususally have less dense precious metal in them, so while they save you a few hundred, you wont get the 100-150k you would out of an OE one.

 

[yesthatsteve]

Using a spark plug anti-fouler might work, or a new O2 sensor at/after the cat. For our Ody, a new O2 sensor did the trick.

 

[Vikas]

You have bunch of options. You can try to clean the converter. Believe it or not, it is claimed that regular laundry detergent will clean it if you can remove it from the car and soak it in it. If that is too much, you can try some made for this job cleaners such as CataClean or CRC GTP or a gallon of lacquer thinner in the 10 gallons of your fuel and then driving the car like maniac for until that gas is used up. These are all of the remedies which have been claimed to work for lot of folks.

If you want personally verified recommendation, get a stainless steel anti-fouler and forget about it forever. The first one was purchased in 09/2007. It is still on the vehicle doing its job.

 

[yonyon]

Assumin you have no exhaust leaks and the car runs well:

With mostly local driving, maybe a good long highway run would help?

If you just want the light off the non-fouler should work. The spring-clamp trick is probably quicker if you have a little spring clamp of the right size. That said, neither of these will make your exhaust emissions any cleaner. Replacing the cat or adding heat shields can actually turn off the light and clean up your emissions but will cost more. It's your call.

 

[Vikas]

A good running Toyota or Honda with cat efficiency light means his emissions are still at zero even in a stringent state such as California. The tail pipe emission will be clean. Those codes are turned on when the efficiency falls below 90%. You will pass the emission until the efficiency falls below 20%

 

[yonyon]

Originally Posted By: Vikas
A good running Toyota or Honda with cat efficiency light means his emissions are still at zero even in a stringent state such as California. The tail pipe emission will be clean. Those codes are turned on when the efficiency falls below 90%. You will pass the emission until the efficiency falls below 20%


For looser definitions of zero.

 

[ARCOgraphite]

Look at fuel trims, misfires counts and sensor recovery frequency FIRST. Dont ignore this there may be an underlying fuel delivery or ignition issue. Only if this is OK proceed with the italian cat tuneup. Most folks drive like grandma and the cat runs too cold and get sooted and suflured up. I drive hard but then drove HARDER and my NEW cat on my NEW car was burning sulfur when I parked. Smoking out the pipe like a coal engine. Fuel up here is absolute garbage.

 

[ARCOgraphite]

You can use one gallon can Toluol from the hardware paint section with a tank of gas to make a clean burning fuel. Toluene is a component of quality gas. I would not go that heavy as you dont have proper cosolvents and inhibitors and lubes in it- id start with a pint on the 3-5 gallons and add a tsp of USP mineral oil to it. This stuff eats through almost anything - almost as bad as Xylene.
- On second thought - forget it.

 

[dailydriver]

Originally Posted By: yonyon
Replacing the cat or adding heat shields can actually turn off the light and clean up your emissions but will cost more.


Huh??

(By causing the catcon to run hotter??)

 

[mechtech2]

Cat codes can be the cat or either O2 sensor.
With high miles, it won't really hurt to replace them [throw parts at it].
But you may have to get an expensive cat, anyways - maybe.

 

[PandaBear]

Thanks for the advice. I don't think I'll use non fouler to make it goes away, but I'll probably replace all the O2.

 

[Vikas]

Use the cleaner first. Watch the both O2 voltages before replacing them.

 

[yonyon]

Originally Posted By: dailydriver
Originally Posted By: yonyon
Replacing the cat or adding heat shields can actually turn off the light and clean up your emissions but will cost more.


Huh??

(By causing the catcon to run hotter??)


Yes. That's the nice thing about obvious solutions. They tend to work.

If the cat is bad enough it won't work and it won't bring NOx down, but for any cat that still "works" the oxidation efficiency will go up. So long as oxidation is above threshhold value during monitor phase you don't get P0420 or P0430 and and there's no need to try fooling the computer. This won't help with a "dead" cat, but PandaBear probably doesn't have that problem.

 

[JHZR2]

Given that you are in the CA, where emissions is so important, Id definitely start by swapping the O2 sensors on the bank (If it were me, Id probably just do all four at once).

A new OE cat on my 91 BMW was only $1600, so I cant imagine yours will be that expensive if you need to do it.

 

[PandaBear]

A new Walker CalCat is $400 before shipping and rebate ($50) so that's not bad in the worst case if I need to replace it.

 

[The Critic]

Originally Posted By: ARCOgraphite
Look at fuel trims, misfires counts and sensor recovery frequency FIRST. Dont ignore this there may be an underlying fuel delivery or ignition issue. Only if this is OK proceed with the italian cat tuneup. Most folks drive like grandma and the cat runs too cold and get sooted and suflured up. I drive hard but then drove HARDER and my NEW cat on my NEW car was burning sulfur when I parked. Smoking out the pipe like a coal engine. Fuel up here is absolute garbage.


Use the Techstream to check this. I think it is under the power train section? I forgot...