By default a MEP does not send CCMs. Use the cci-enabled command in MEP configuration mode to enable the sending of CCMs for this MEP.
This example shows how to enable the sending of continuity check messages for MEP 1000 on myMA1:
System(rw-config)->cfm md string-name myMD1 System(su-config-cfm-md.1)->ma string-name myMA1 System(su-config-cfm-ma.1)->mep 1000 System(su-config-cfm-mep.1000)->cci-enabled System(su-config-cfm-mep.1000)->enable System(su-config-cfm-mep.1000)->