ORA-15149: another ASM instance found running on the host

[grid@testdb1 ~]$ sqlplus / as sysasm

SQL*Plus: Release 11.2.0.3.0 Production on Mon Apr 3 16:34:25 2017

Copyright (c) 1982, 2011, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup

ORA-00099: warning: no parameter file specified for ASM instance

ORA-15149: another ASM instance found running on the host

[grid@testdb1 ~]$ export ORACLE_HOME=/opt/grid/product/11.2.0.3/

[grid@testdb1 ~]$ export PATH=/opt/grid/product/11.2.0.3/bin/

[grid@testdb1 ~]$ export ORACLE_SID=+ASM

SQL> select instance_name from v$instance;

INSTANCE_NAME

----------------

+ASM