the engine in your car needs to have EGR, exhaust gas recirculation. this is done with ''egr valve'' on the rear of the driver side intake
manifold and a pipe, (about 3/8 dia.) that connects the ''egr valve'' to the rear of the driver side head. the pipe is shaped like a staple '']''.
if your engine does not have this ''egr'' it will throw a code and there is no way to clear it.
i don't know if this is your problem but it would not be the first ej22 swap to have it.
items #9 and #13 are the easiest to identify.