We have found that many of these vehicles are receiving an improper signal from the original mass air sensor. When replacing the catalytic converter on vehicles equipped with the AEG engine (6 bolt catalytic converter inlet flange), it is imperative that the mass air sensor, and upstream oxygen sensor be replaced at the same time.
Failure to replace these components will likely cause the new converter to either break internally, or rendered inoperative by substrate coating, both a result of improper fuel mixture during the drive cycle. Either issue usually results in check engine light, and catalyst code, and is not covered by the catalytic converter warranty.