P0240 2nd cat Options

[xrav22]

Hey there I have been reserching this code (p0240)for a while now and now need some help.

It states my 97 GT has a weak catalytic converter #2. Now since this started I am only getting 275 to the tankfull. Before I was getting well over 300.

I gave a complete tune up. I keep shutting the engine light off but it keeps popping on every tankfull or so. When I got a smog I replaced the two 02 sensors by the exaust manifold. The guy at smog said that the top sensor was for fuel ratio and I didn't need to replace it. I replaced both anyways.

I thought both were 02 sensors. So if my problem is cat #2 I am assuming there is another cat halfway back on the car. Before I go crawling under there does anyone know if there is another sensor down there and has anyone replaced that cat with another if so what brand is ok.

I read aftermarket cats don't want to work. Anyways I cant find a pdf or anything that shows that part of the exaust.

Thanks in advance.

[Smaay]

its actually P0420 and it means catalyst is out of range. it could either be your Catalytic converter is dead or the O2 sensor is going bad. there are 2 CATs on the car, one big one thats built into your header, thats where the O2 sensors are. there is another small CAT down the pipe under the car.

yes you can get an aftermarket CAT and it will probably work just fine.

[xrav22]

its actually P0420 and it means catalyst is out of range. it could either be your Catalytic converter is dead or the O2 sensor is going bad. there are 2 CATs on the car, one big one thats built into your header, thats where the O2 sensors are. there is another small CAT down the pipe under the car.

yes you can get an aftermarket CAT and it will probably work just fine.

So I need to get the CAT that is built into the header because the other one is not monitored. Do you think I would be better off at a junkyard and get the header cat, or buying a new cat thet goes into the header. I don't want to go to Toyo for that .