RC 0 = success, RC 4 = warning, RC 8 = error, RC 12+ = severe error, RC 16 = catastrophic. 2. **Read the job log (JESMSGLG, JESJCL, JESYSMSG)** — look for the first error message. 3. **Check SYSPRINT** — compiler listings, utility messages, program output. 4. **Check CEEDUMP or SYSUDUMP** — for aben