I'm guessing the code is actually a P0430...
Anyway, that code typically means you need to replace your catalytic converter(s). I was taught that the cats don't go bad without something else causing it (too much fuel, burning oil, etc), but was told otherwise in one of the stealerships I worked at.
Regardless, according to obd-codes.com, the 3 main causes for this code are:
Catalytic Converter not functioning properly
O2 sensor not reading (post cat)
Check all three before jumping to conclusions, especially since cats are not particularly cheap.
OBD-II Trouble Code: P0430 Catalyst Efficiency Below Threshold (Bank 2)