Catalytic Converter Issues
 

We have a 2006 Honda Pilot EX-L with 207 thousand miles. The check engine was coming on an off for a few days. I hooked up my scan tool (which is not a sophisticated one) and code PO430 came up, which I understand can most likely be an oxygen sensor. However, she took it get the state inspection and the tech at the shop said that she needs a new catalytic converter and that it has three. In doing research, I found a bad converter can throw the same code. The tech said they wouldn't be able tell which converter was bad and she would need to have all three replaced totaling $4,000. We live in Western New York (in the Buffalo area), and in NYS, exhaust parts have to be CARB complaint, so cat converters are more expensive than most states. One, is what he told true her true that they can't determine which one is bad and all three have to be replaced? Two, if he is telling the truth, does anyone in NYS know of a place where we can get CARB compliant cat converters reasonably? Thanks

Replace the all together.

if you go to cheaperhondaparts.com you might find the cats a little lesser in cost.

I live in New York and I feel your pain. Carb compliant cats are very expensive.
Discount converter.com or magnaflow.com are two places I have looked at.
They seem to be the cheapest. But, any tech who is worth their salt should be able to tell which one needs to be replaced.
P0420 is cat below efficiency on bank one and P0430 is cat below efficiency on bank two.
The code tells the tech which side to look at. P0430 is the cat opposite the side where cylinder number 1 is located
With a higher level scanner, the tech should be able to see the graph of the voltage coming from the O2 sensor and see if it is working properly.
Sometimes it isn't the cat but the O2 sensor that is faulty. If you replace the cat and still have the problem then you spent a lot of money for a fix that did not work.
Most people replace the O2 sensor first depending upon the cost. Some O2 sensors are very expensive.
Good luck to you. Please let us know what happens.