This is not another post about trouble code P0420, I promise. I spent two hours last night reading everything I could about that code -- cat replacement, cat gutting, ways to override MIL, etc. My question, though, is related. I recently pulled this code on my OBD-II analyzer. When I had my original engine, all the cats were replaced under recall when this same code was pulled. Now, however, I have a used engine installed thanks to burning up my original engine when the water pump went. My question: I would love to go back to the dealership and say, "I already had the cats replaced under recall and now it's looking like one or more of them is dying." Will the dealer be able to tell that the used engine, which is from a 96, is not my original, which was a 97? I feel "OK" about trying this approach because whoever owned the 96 engine with the cats that are potentially failing now would have qualified for the cat recall in the first place. Or am I risking the dealer "catching me" trying to fool them? I have the recall repair work receipt. Thanks!
