Not sure what I used it for, but here is a simple program in assembler to create an ABEND with a completion code of your choice.

Look here in the IBM manuals for more specifics on the ABEND macro.

ABENDIT  CSECT
         EQUATES
         SAVE  (14,12),,ABENDIT/OURDEPT/&SYSDATE/&SYSTIME/
         USING ABENDIT,R11             SET UP BASE ADDRESSABILITY
         LR    R11,R15                 LOAD BASE REG WITH ENTRY POINT
         LA    R14,SAVE                GET ADDRESS OF REGISTER SAVE
         ST    R13,4(0,R14)            SAVE CALLER'S SAVE AREA ADDR
         ST    R14,8(0,R13)            SAVE MY SAVE AREA ADDRESS
         LR    R13,R14                 LOAD SAVE AREA ADDRESS
*        Business Logic
         ABEND 4321                    4321 or some other code up to 4096
*        Epilogue
RETURN   EQU    *
         L      R13,4(R13)
         RETURN (14,12)                RETURN TO CALLER
         LTORG
SAVE     DS     18F
         END ABENDIT

Happy ABENDing!