Using GJTRABTR, you can code a job that when receiving anything other than a RC=0000, will receive a TRACWARN message.
You want to use GJTRABTR to add a job that should complete with completion code of 0000. If the job you add has any other completion code then 0000, you want to make sure you will see a TRACWARN message.
To accomplish this, code the following;
ADD (JOB(jobname) MAXCC(0000))