change SYSMAN password

When changed SYSMAN password  in database the Enterprise Manager doesn't care this case.

You have to change password manually.
you can apply following directions

1 - cd emoms.properties config file directory. open file your editor like vi.

cd $ORACLE_HOME/"hostname"_"SID"/sysman/config/

change  values hostname and SID your values for above command.
2-
change oracle.sysman.eml.mntr.emdRepPwdEncrypted   parameter to  FALSE
change oracle.sysman.eml.mntr.emdRepPwd to your SYSMAN password without encyrpted

save file

3-
emctl start dbconsole

4- check emoms.properties config file which has encrpyted password.

You can use your console.