When a RAC is turned on, it will try to accessing the OCR registry which is located on ASM. ASM also holds the asm password file. However to open ASM, it needs to access the password file.
If the password file is missing or corrupted etc... when turning on the CRS stack, this happens:
2016-01-12 12:00:51.317680*:kgfo.c@1115: kgfoSaveError: ignoring existing error: ORA-01017: invalid username/password; logon denied ORA-15077: could not locate ASM instance serving a required diskgroup
Oracle's solution to this is the following:
You can make a backup of the Oracle ASM password file, and if the Oracle ASM password file is lost or the disk group becomes inaccessible, then you can restore the backup password file.
Even if ASM is working, how can it access the password file which is inside ASM if it needs a password to access ASM?