hey guys, my friends dont belong to a message board so they asked me to ask you guys a quick Q.. they have a 01 toyota celica, i know this is "honda"-tech. but i thought you would probly know the answer.. they took out all the honey combs in their cat and today for the first time since their check engine light came on, so they took it to a shop and hooked it up to the comp.. and it was throwing a exhaust code.. the mechanic said it was b/c the honey comb had been taken out of the cat. but here's my Q, if they had bad 02 sensors would it throw the same code?? thanks

 

the code usually isn't specific it just reads secondary o2 or primary o2, that is if you are just grabbing the code yourself with out a diagnostic tool. It is because you gutted the cat, I had the same problem when I gutted mine. You can find o2 simulators every once and a while, or you could spend 100 bucks and get a high flow cat. You're probably not going to gain any noticable horsepower with just gutting the cat anyway.