If an OBD II PCM Has Set a Catalyst Efficiency

If an OBD II PCM has set a catalyst efficiency code, all of the following pre-checks should be performed before condemning the converter EXCEPT for:

A) checking the exhaust system for any leaks
B) using a scan tool to check for O₂ sensor codes
C) visually checking the O₂ sensors for cracked housings
D) verifying that the engine does not have excessive cycling