If the monitor cannot display error messages during the 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 the POST. Most beep codes indicate a fatal error that prevents the system from
completing the boot routine until the indicated condition is corrected.
| Beep Code |
Error |
Probable Cause |
| 1-3 |
Monitor not detected |
Disconnected or faulty monitor |
| 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 memory installed |
No memory 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 system board) |
| 3-4-1 |
Screen-retrace test failure |
Faulty video subsystem (defective system board) |
| 3-4-2 |
Search for video ROM failed |
Faulty video subsystem (defective system board) |
| 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 DIMM |
| 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-port test failure |
Faulty I/O chip (defective system board) |
| 4-4-2 |
Parallel-port test failure |
Faulty I/O chip (defective system board) |
| 4-4-3 |
Math coprocessor failure |
Faulty microprocessor chip or system board |
| 4-4-4 |
Cache test failure |
Defective microprocessor or system board |
