Cannot startup Oracle due to ORA-15041 I'm troubleshooting an Oracle instance that won't startup  due to ORA-15041. The trc file shows this error:

Failed to create file '+FRA_DATA' (file not accessible?)
ORA-19816: WARNING: Files may exist in db_recovery_file_dest that are not known to database.
ORA-17502: ksfdcre:4 Failed to create file +FRA_DATA
ORA-15041: diskgroup "FRA_DATA" space exhausted
*************************************************************
WARNING: A file of type ARCHIVED LOG may exist in
db_recovery_file_dest that is not known to the database.
Use the RMAN command CATALOG RECOVERY AREA to re-catalog
any such files. If files cannot be cataloged, then manually
delete them using OS command. This is most likely the
result of a crash during file creation.
*************************************************************
ORA-19504: failed to create file "+FRA_DATA"
ORA-17502: ksfdcre:4 Failed to create file +FRA_DATA
ORA-15041: diskgroup "FRA_DATA" space exhausted
*** 2016-02-22 11:10:10.612 4132 krsh.c
ARCH: Error 19504 Creating archive log file to '+FRA_DATA'
*** 2016-02-22 11:10:10.612 2747 krsi.c
krsi_dst_fail: dest:1 err:19504 force:0 blast:1
DDE: Problem Key 'ORA 312' was flood controlled (0x1) (no incident)
ORA-00312: online log 1 thread 1: '+RAC_DATA/oradb/redo01.log'
ORA-16038: log 1 sequence# 11427 cannot be archived
ORA-19504: failed to create file ""
ORA-00312: online log 1 thread 1: '+RAC_DATA/oradb/redo01.log'

*** 2016-02-22 11:10:10.685
USER (ospid: 25801): terminating the instance due to error 16038
ksuitm: waiting up to [5] seconds before killing DIAG(25722)


Is there a way to manage this with no connection to the database? So far all the solutions I have encountered from research requires a database connection, however I cannot even get the instance up.

Very new to database troubleshooting (actually a web developer), just tasked to troubleshoot this as our DBA left. Any help would be very much appreciated. 

TIA!
ORA-15041: diskgroup space exhausted
Cause:  At least one disk in the diskgroup is out of space.
Action: If all disks are evenly balanced, add more disks to the diskgroup.

According to the log provided in the question, i found that it was unable to complete the archiving operation as the asm diskgroup '+FRA_DATA' is full. The DML operation on large table might have caused this error.
You can check if there are extra files - including orphaned archivelogs - that may be in the FRA_DATA.

RMAN>crosscheck archivelog all;

If there is no more space available in FRA_DATA then add disks to diskgroup using ASMCA or ASMCMD utilities. 
After adding disks to the diskgroup also check the value of db_recovery_file_dest_size initialization parameter.
The error 15041 possibly relates to the disks in that particular diskgroup.
This can happen if the Diskgroup contains disks of unequal sizes.
See Oracle Support Document ORA-15041 IN A DISKGROUP ALTHOUGH FREE_MB REPORTS SUFFICIENT SPACE (Doc ID 460155.1)