Subaru Forester Catalytic Converter and Check-Engine Light

During the last 5 months, the check-engine light for my 2000 Subaru Forester has come on for three separate events. Two of them involved the catalytic converter. I have had it replaced twice within 3 months. The light came on again yesterday (less than a month after the second converter was installed. Anyone have any ideas?

It would be best to post the actual codes that are coming up re the check engine light. Obviously these are pointing someone to the cat, but at this point it seems likely that the cat isn’t the problem.

Do you know what the actual codes were/are? If so post them (a letter/number like P0123).

probably a sensor that’s going bad

I don’t know the codes … the mechanic said that it indicated the catalytic converter. One of oxygen sensors failed and was replaced by a Dealer (under warranty). The mechanic took a day to test the car, before he replaced the catalytic converter for the second time. He thought that the Dealership should have replaced both oxygen sensors, and that possibly weak sensor and a new sensor would indicate a failed converter … but he replaced the converter (this makes 3 catalytic converters for this car in a little over 100k miles).

check my recent question/discussion "aftermarket catalytic converter for mercury sable '97 does not work- may be the comments of this discussion will help-

was the cat. converter still under warranty when replaced for the second time? did you receive a warranty card for your converter? If your car has now an aftermarket converter or one that is not compatible with your car, there might be the problem.
Find out the manufacturer, part #.