Make sure you are doing the right sensor - bank #2 is actually the front of the engine bay, bank #1 is the side closest to the passenger compartment. Whoever gave you the code should have mentioned which bank the code came from.
Do you have the actual code? P#### format
Not having the same connector doesn't sound right to me. Are you absolutley sure you have the correct sensor?
You should reset the PCM (pull fuses #4 and 11 or neg battery cable) to clear the code. Especially if it is the rear O2 sensor - the Cat Monitor test runs VERY infrequently and the CEL won't go of until it does (and passes).
Cat replacement is big $$$ - you are replacing the exhaust manifold. Not cheap, and not a small job labor wise.
