catalytic converters

Hello all I have a few questions about the cats on this van. I'm getting a po430 code which is bank 2 cat system efficency below threshold the problem is this vehicle only has 1 cat so there would be no bank 2 the computer has been swapped from a junk yard and I don't know the Vin of the junkyard vehicle. I don't know what to do.

Hello all I have a few questions about the cats on this van. I'm getting a po430 code which is bank 2 cat system efficency below threshold the problem is this vehicle only has 1 cat so there would be no bank 2 the computer has been swapped from a junk yard and I don't know the Vin of the junkyard vehicle. I don't know what to do.

Year make and model and engine would help.
Why was computer switched?
Do you still have original computer?

Oh sorry it's a 1997 Chevrolet 1500 van with a 5.0 I'm not sure why the computer was switched that is what I was told. And no they don't still have the original

Oh sorry it's a 1997 Chevrolet 1500 van with a 5.0 I'm not sure why the computer was switched that is what I was told. And no they don't still have the original

The computer system for a 97 chev. express van 5.0 v8 is set up for bank 1 and bank 2 cats or sensors.
Better check your exhaust system for missing or bad cat and or 02 sensors.

Where computer has been switched the problem could be there.
If I was trying to fix it.
I would get it on a engine capable scanner and watch and check 02 sensor readings.
And make sure it has the right computer /prom set up.
Let us know how it goes.