RAC SCAN Listener

Hi - SCAN listener is configured and all other instances are connecting to SQL plus using scan listener.But one instance is connecting to sqlplus if you use scan listener connect string.

$lsnrctl status LISTENER_SCAN1 is NOT showing the instances even though the intialization parameter is mentioned.

remote_listener                      string      node01-scan:1521

tnsping is working fine.The problem is with sqlplus@govtd_scan

How to add the instnace names to scan listener?

We are using two node RAC.DB version is 11g Rel2.

Thanks in advance.