Yes you should still pass emissions, you are not taking out the Cat only fooling the computers measurements of flow both pre and post cat.

See pictures:

The effecient cat would be a stock cat. Note flow post cat. Slows down the air.

The ineffecient cat is what happens when we cut or use a hiflow cat.

The rear 02 sensors function is to measure air flow, when we have no restrictions to the flow (i.e. no cat) then it will cause a SES light.

 

yes, it has nothing to do with emissions...just tricks your o2 sensor because it spaces it a bit off of the pipe.

on the other hand, i dunno about passing emissions with your hi flow cat. i would just put your stock cat back on when you go to get tested.

 

O2 simulator would be your best bet, but it is the high flow cat thats causing that code.

 

Sorry to raise this post up from the dead but i have a question relating to this code. Whats more likely to cause this code:
1. an ecu flash
2. leaded fuel
I am 99% sure its the leaded fuel someone gave me poisoning my cat. (no I did not know the fuel was leaded, I should have asked). Also if I drain the tank and replace it with pump fuel then reset the code will it come back or is the stock cat shot like I'm thinknig it is? Could leaded fuel mess up the O2 sensors as well? I estimate about 2.5 gals of the fuel was burned before my SES light came on.

I hope the problem works itself since I have a stock exhaust sytem and I would like the ability to pass emmisions tests if I ever need to. I've also heard that doing the mechanical CEL on the stock exhaust put the O2 housing in a dangerous location.