In the FND_CONCURRENT_QUEUE table we have a column named control_code.
To get the details of the code present in the column we can use below script.
SQL> select lookup_code,meaning from apps.fnd_lookups where lookup_type = 'CP_CONTROL_CODE' order by lookup_code;
LOOKUP_CODE MEANING
---------- ------------------------------
A Activating
B Activated
D Deactivating
E Deactivated
H System Hold, Fix Manager before resetting counters
N Target node/queue unavailable
O Suspending concurrent manager
P Suspended
Q Resuming concurrent manager
R Restarting
T Terminating
U Updating environment information
V Verifying
X Terminated