Newby here just swapped my wore out Cirrus for a 2006 Sebring. Sebring has 100K on the meter but so far seems in good shape. Check engine light is on and neighbor with a diagnostic tool says one of the cats has failed but he cant tell which one as he dosen't know how to operate his tool. So my question to the forum, would a average full servcie garage (not dealer) be able to tell me which of the 4 cats has failed.

 

what are the code numbers

 

The answer to your question is "yes". As Tech points out, if you know the error code numbers, it will tell you which catalytic converter is bad. There is only one cat on the four cylinder engine and there are two cats on the six cylinder engine (one on each bank of cylinders).