EC5

Explanation
JES common coupling services (JESXCF) detected
an unrecoverable error that causes the JES member to terminate abnormally.
The hexadecimal reason code returned in register 0 describes the error: Code
Explanation
00
An error was detected in the JESXCF recovery environment.
04
The application was terminated for consuming excessive JESXCF
resources.

System action
The system abnormally terminates
the JES member or application.

Operator response
Notify your system programmer.

System programmer response
Find the associated
JESXCF or application abend and the associated dump. Use these to
diagnose the error. If the problem is due to a coding error, search
the problem reporting data bases for a fix to the problem. Fix the
problem and restart JES. If no fix exists, contact the IBM® Support Center with the return and reason
codes and the dumps produced by the error.
For additional information
on dumping JES and JESXCF address spaces, as well as restarting the
JESXCF address space, see z/OS MVS Programming: JES Common Coupling Services.

Source
JES common coupling services (JESXCF)