Anyone else have a `00 diamante with only one cat? I have one, and a po420 code keeps coming up. The weird thing is that all the auto parts places are telling me I should have 3 cats!! And they have the diagrams to show me that. Does anyone know if a diamante was ever built with only 1 cat, or should I assume mine was messed with. Mine was built in Australia in Oct 99. The exhaust all fits well (walker components) and only has the main cat and 2 o2 sensors.

 

The second generation Diamante (97-04) was sold as either Federal-specified or California-specified models. The Federal model had one cat. The California model had two additional small cats, one immediately after each exhaust header, for a total of three.

The parts places probably only have the diagram for the California-specified system with the 3 cats. If you visit Auto Parts - Parts.com you will see the two different exhaust systems in the diagrams on the bottom left side of the page. The prices on that website are pretty good, too, and they are genuine Mitsubishi.