P0420 and bad mileage

[IdleWild]

I'm having a CEL of P0420 for awhile already on my 2002 Camry LE with 140K miles on it, and when before i could easily make 400+ miles from full tank,now it never reaches 350... I know from googe and these threads that the problem could be either O2 sensor or cat converter.. Toyota dealership couldn't identify the problem. Tech said he couldn't test O2 sensor, because "it could break when coming out"; also he said that cat converter looked all rusty and most likely that's the source of the problem, so he nicely offered a repair for around 1 grand, which would include cat converter,reprogramming ECU and labour.

So this is what i could do. I could buy for around $430 both O2 sensors(there are only on my model 2 if i'm not mistaken) and a cat converter and put them all in by myself.

I don't know why reprogramming ECU is reqired (if the tech is right), could someone explain that process to me?
And how much would i expect to pay for reprogramming ECU, if anyone had any experience with that... ?

And one more thing, if i just buy 2xO2 sensors without changing cat converter, to see if the problem is fixed, is it possible that bad cat converter can ruin new O2 sensors or vice versa ?

Thanks guys in advance!

[TRD VVTi]

Originally Posted by IdleWild

I'm having a CEL of P0420 for awhile already on my 2002 Camry LE with 140K miles on it, and when before i could easily make 400+ miles from full tank,now it never reaches 350... I know from googe and these threads that the problem could be either O2 sensor or cat converter.. Toyota dealership couldn't identify the problem. Tech said he couldn't test O2 sensor, because "it could break when coming out"; also he said that cat converter looked all rusty and most likely that's the source of the problem, so he nicely offered a repair for around 1 grand, which would include cat converter,reprogramming ECU and labour.

So this is what i could do. I could buy for around $430 both O2 sensors(there are only on my model 2 if i'm not mistaken) and a cat converter and put them all in by myself.

I don't know why reprogramming ECU is reqired (if the tech is right), could someone explain that process to me?
And how much would i expect to pay for reprogramming ECU, if anyone had any experience with that... ?

And one more thing, if i just buy 2xO2 sensors without changing cat converter, to see if the problem is fixed, is it possible that bad cat converter can ruin new O2 sensors or vice versa ?

Thanks guys in advance!

The oxygen sensors can be checked to see if they're functioning properly by an experienced technician.

A faulty convertor can damage oxygen sensors.

There is a TSB (Technical Service Bulletin) regarding this issue and performing a simple search will easily locate that thread for you.

Programming the ECU is necessary when replacing a faulty convertor per the TSB. Expect to pay 1 hour labor, possibly 1 1/2 hours labor.

[IdleWild]

Thanks for reply TRD VVTi.

I was about to get the converter, here's the picture
but seller told me that this converter is not the monitored one and it would not set the CEL, and that the part that I need is this one

Can you confirm that?

Could I better get something like that instead ?
http://cgi.ebay.com/ebaymotors/OBX-E...ayphotohosting ?