Subaru catalytic converter problems

I own a 2000 Subaru Legacy wagon with 106,000 miles. In the past 8 months the CEL has been on nearly constantly, each time the code indicates a catalytic converter problem. Since January, I’ve replaced the converter (the larger unit which houses two of the three converters) twice – once because of the CEL and the second time because my mechanic believed that the unit was “bad” when the light came on again. Two oxygen sensors have also been replaced to no avail. Are there other issues that could contribute to this code coming up? Any advice is greatly appreciated…

It sounds like your mechanic is just guessing and throwing parts at the problem, at your expense. No error code explicitly says to replace the catalytic converter. Go to a chain auto parts store like Auto Zone and have them scan the car for diagnostic error codes, and post back with the actual code(s).