If the monitor cannot display error messages during POST, the system may emit a series of beeps that identifies the problem or that can help you identify a faulty component or assembly. The following table lists the beep codes that may be generated during POST. Most beep codes indicate an error that may prevent the system from completing the boot routine until the indicated condition is corrected.
| Beep Code | Error | Probable Causes |
| 1-1-3 | NVRAM write/read failure | Defective system board |
| 1-1-4 | BIOS checksum failure | Faulty BIOS or defective system board |
| 1-2-1 | Programmable interval-timer failure | Defective system board |
| 1-2-2 | DMA initialization failure | Defective system board |
| 1-2-3 | DMA page register write/read failure | Defective system board |
| 1-3-1 | Main-memory refresh verification failure | Faulty or improperly seated DIMM or defective system board |
| 1-3-2 | No 100-MHz DIMM installed | No 100-MHz DIMM installed or faulty or improperly seated DIMM |
| 1-3-3 | Chip or data line failure in the first 64 KB of main memory | Faulty or improperly seated DIMM |
| 1-3-4 | Odd/even logic failure in the first 64 KB of main memory | Faulty or improperly seated DIMM |
| 1-4-1 | Address line failure in the first 64 KB of main memory | Faulty or improperly seated DIMM |
| 1-4-2 | Parity failure in the first 64 KB of main memory | Faulty or improperly seated DIMM |
| 2-1-1 through 2-4-4 | Bit failure in the first 64 KB of main memory | Faulty or improperly seated DIMM |
| 3-1-1 | Slave DMA-register failure | Defective system board |
| 3-1-2 | Master DMA-register failure | Defective system board |
| 3-1-3 | Master interrupt-mask register failure | Defective system board |
| 3-1-4 | Slave interrupt-mask register failure | Defective system board |
| 3-2-4 | Keyboard-controller test failure | Faulty keyboard controller (defective system board) |
| 3-3-4 | Screen initialization failure | Faulty video subsystem (defective graphics adapter card) |
| 3-4-1 | Screen-retrace test failure | Faulty video subsystem (defective graphics adapter card) |
| 3-4-2 | Search for video ROM failure | Faulty video subsystem (defective graphics adapter card) |
| 4-2-1 | No timer tick | Defective system board |
| 4-2-2 | Shutdown failure | Defective system board |
| 4-2-3 | Gate A20 failure | Defective system board |
| 4-2-4 | Unexpected interrupt in protected mode | Defective system board |
| 4-3-1 | Memory failure above address 0FFFFh | Faulty or improperly seated DIMMs |
| 4-3-3 | Timer-chip counter 2 failure | Defective system board |
| 4-3-4 | Time-of-day clock stopped | Bad battery or defective system board |
| 4-4-1 | Serial/parallel port test failure | Faulty I/O chip (defective system board) |