odb code p0420 camry

I just had my catalytic converter done (2000 camry le 4 cylinder) and finally drove enough to get the computer reset. It finally came up P0420. It says catalyst system effiecency below threshhold. Is there a different problem then what I spent $400. on? Thanks, Geoff

 

Toyotas are notorius for these problems.

Most people end up shotgunning parts until it's fixed.
I recommend getting this car hooked up to a scan tool to get the readings off the O2 sensors. Both the sensors should be similar. If they are not, you need to replace an O2 sensor, if they are both good, you got another bad Cat.

 

That code is set when the computer sees a difference in toggle speed (Rich/Lean) from the forward O2 and the rear O2..........Normally I RECOMMEND changing the O2's at the same time as the convertor.........ESPECIALLY if it's an older high mileage car......

 

Originally the check engine light was on. Eventually the car ran not so smooth which is when I took it in. The original mechanic scanned it and said I needed an O2 sensor which he changed using an original toyota $208. sensor (seemed high) plus labor. He also said I may need a catalytic converter since that code came up also. He also suggested I get a new flex pipe which had a small leak and the car did seem noisier then usual. He did say the cat code may be a false code from the O2 sensor or from the flex pipe leak. Both the 02 and flex pipe were done the same day, the flex from a muffler chain he recommended. One week later after clearing the codes after the flex and O2 was done, the cat code came back after the computer reset. Now that I did the cat, so far after about 80 miles, I have a "pending P0420" which is where I am now. Sounds like I should change the second 02 sensor by the catalytic converter. The other thing the code says is cat effiecientcy below threshhold bank one. I forgot the bank one part. Wires and plugs (both toyota) were done recently. Thanks for your help.

 

"bank One" is kinda funky for a 4 banger............as you only HAVE one bank.......I woould think about the second O2............I'd be willing to wager a guess that it will put this problem to rest

 

oh yea, 185,000 miles. Will get 02 sensor. I am not sure how much scanner for the 02 sensors cost. I only have OBD and a multitester. Thanks.

 

Thanks for your reply wrench. You think I might have only needed an 02 to begin with?

 

Thanks HOTinOKC and Wrench. Just left the mechanic who said he will replace the cat since occasionally they are bad (after market from a chain)and also place it further back from the O2 sensor. Will let you know outcome.

 

Could have been......The code actually sets because of what the computer "sees" the O2's doing............but understand.........Both cat convertor AND O2 sensors have a life expectancy of about 50,000 miles........If you are in the 180,000 bracket, they have more than done their job.

 

The mechanic erased codes the other day and now I get P0401 - EGR insufficient air flow. I am hoping when he puts in new cat, this will go away. The cat code is still not ready after 100 miles. Once the cat is ready, I wonder if 420 will return.

 

Nope..........The Cat won't cure the EGR..........Put vacuum to the valve itself (at idle) and see if the car stalls or runs real rough..........I'm betting it will as these don't usually clog or fail.............9 times out of 10 the problem is the EGR vacuum amplifier........The little round thinga ma bob that sits behind the intake and has vacuum hoses to the EGR

 

It was a pending code (PO401) but never materialized, so it is not saved in the computer. Still waiting for cat sensor to be ready. Muffler chain still plans on changing cat this afternoon. Taking car for another ride which will hopefully ready the cat sensor so I can get my car inspected. Thanks, again.

 

Muffler chain just put 3rd Cat in. Will advise once computer resets. I don't think this is the answer. Now I have my oil light blinking if the car idles slow and with 190,000 miles, this may be the end. -Thanks, Geoff