Each hardware manufacturer has its own diagnostic codes that identify specific POST errors and you will need to know these for the A+ Certification Exam. You need to consult the manufacturer documentation for the diagnostic codes for your hardware, but the general breakdown of the code categories is as follows:

  • 100–199: Motherboard error

  • 200–299: Memory error

  • 300–399: Keyboard error

  • 600–699: Floppy drive error

  • 1400–1499: Printer error

  • 1700–1799: Hard drive error