When you turn the computer on, it performs Power On System Test (POST),
during which it checks and initializes the system's internal components.
If a serious error occurs, the computer does not display a message but emits
a series of long and short beeps instead.
Beeps are your computer's way of letting you know what's going on when the
video signal is not working.
These codes are built in to the BIOS of the PC.
There is no official standard for these codes due to the many brands of BIOS
that are out there.
To decode the meaning of your computer POST beep codes you must consult the
manual of your motherboard.
If you don't have a motherboard manual or if it's incomplete you must search
on the site of your computer manufacturer.
Another way is take off the computer case and look for BIOS manufacturer (just
see if it says "AMI" or "Phoenix" ...).
For more information about BIOS and how to identify it please check this site: Wim's
BIOS Page - Everything you want to know about BIOS.
Once you have determined your BIOS make, consult the following tables to see
what's wrong with your computer.
The following are AMI BIOS Beep Codes that can occur. However because of the wide variety of different computer manufacturers with this BIOS the beep codes may vary.
| Beep Code | Descriptions |
|---|---|
| 1 short | DRAM refresh failure |
| 2 short | Parity circuit failure |
| 3 short | Base 64K RAM failure |
| 4 short | System timer failure |
| 5 short | Process failure |
| 6 short | Keyboard controller Gate A20 error |
| 7 short | Virtual mode exception error |
| 8 short | Display memory Read/Write test failure |
| 9 short | ROM BIOS checksum failure |
| 10 short | CMOS shutdown Read/Write error |
| 11 short | Cache Memory error |
| 1 long, 3 short | Conventional/Extended memory failure |
| 1 long, 8 short | Display/Retrace test failed |
| Short Beep | Long Beep | Short Beep | Descriptions |
|---|---|---|---|
| 3 | 1 | - | Flash loader failure |
| 3 | 2 | - | Failure in system board component |
| 3 | 3 | - | Failure in system board component |
| 3 | 4 | - | Memory failure |
| 3 | 5 | - | Video failure |
| 0 | 6 | - | Flash BIOS update error |
| - | 2 | x | AST low level diagnostics |
| Beeps | Error Message | Description | Resolution |
|---|---|---|---|
| 1 | Refresh Failure | The memory refresh circuitry is faulty. | Reseat the memory SIMMs. If the system still beeps, replace the memory. |
| 2 | Parity Error | Parity error in the base memory (the first 64 KB block) of memory. | Reseat the memory SIMMs. If the system still beeps, replace the memory. |
| 3 | Base 64 KB Memory Failure | Memory failure in first 64 KB. | Reseat the memory SIMMs. If the system still beeps, replace the memory. |
| 4 | Timer Not Operational | A memory failure in the first 64 KB of memory, or Timer 1 is not functioning. | The motherboard must be replaced. |
| 5 | Processor error 8042 - Gate A20 Failure | The CPU generated an error. | The motherboard must be replaced. |
| 6 | 8042 - Gate A20 Failure Processor Exception Interrupt Error | Cannot switch to protected mode. | Try a different keyboard, or replace the keyboard fuse, if the keyboard has one. |
| 7 | Processor Exception Interrupt Error | The CPU on the CPU Card generated an exception interrupt. | The motherboard must be replaced. |
| 8 | Display Memory Read/Write Error | The system video adapter is either missing or its memory is faulty. This is not a fatal error. | There is a memory error on the video adapter. Replace the video adapter, or the RAM on the video adapter. |
| 9 | ROM Checksum Error | The ROM checksum value does not match the value encoded in WINBIOS. | The BIOS ROM chip is bad. The system probably needs a new BIOS ROM chip. |
| 10 | CMOS Shutdown Register Read/Write Error | The shutdown register for CMOS RAM has failed. | The motherboard must be replaced. |
| 11 | Cache memory bad - do not enable cache | The cache memory test failed. Cache memory is disabled. Do not press Ctrl/Alt/Shift <+> to enable cache memory. | The motherboard must be replaced. |
The following are IBM BIOS Beep Codes that can occur. However because of the wide variety of models shipping with this BIOS the beep codes may vary.
| Beep Code | Descriptions |
|---|---|
| No Beeps | No Power, Loose Card, or Short. |
| 1 Short Beep | Normal POST, computer is ok. |
| 2 Short Beep | POST error, review screen for error code. |
| Continuous Beep | No Power, Loose Card, or Short. |
| Repeating Short Beep | No Power, Loose Card, or Short. |
| One Long and one Short Beep | Motherboard issue. |
| One Long and Two short Beeps | Video (Mono/CGA Display Circuitry) issue. |
| One Long and Three Short Beeps. | Video (EGA) Display Circuitry. |
| Three Long Beeps | Keyboard / Keyboard card error. |
| One Beep, Blank or Incorrect Display | Video Display Circuitry. |
PHOENIX BIOS Q3.07 OR 4.X
| Beep Code | Descriptions / What to Check |
|---|---|
| 1-1-1-3 | Verify Real Mode. |
| 1-1-2-1 | Get CPU type. |
| 1-1-2-3 | Initialize system hardware. |
| 1-1-3-1 | Initialize chipset registers with initial POST values. |
| 1-1-3-2 | Set in POST flag. |
| 1-1-3-3 | Initialize CPU registers. |
| 1-1-4-1 | Initialize cache to initial POST values. |
| 1-1-4-3 | Initialize I/O. |
| 1-2-1-1 | Initialize Power Management. |
| 1-2-1-2 | Load alternate registers with initial POST values. |
| 1-2-1-3 | Jump to UserPatch0. |
| 1-2-2-1 | Initialize keyboard controller. |
| 1-2-2-3 | BIOS ROM checksum. |
| 1-2-3-1 | 8254 timer initialization. |
| 1-2-3-3 | 8237 DMA controller initialization. |
| 1-2-4-1 | Reset Programmable Interrupt Controller. |
| 1-3-1-1 | Test DRAM refresh. |
| 1-3-1-3 | Test 8742 Keyboard Controller. |
| 1-3-2-1 | Set ES segment to register to 4 GB. |
| 1-3-3-1 | 28 Autosize DRAM. |
| 1-3-3-3 | Clear 512K base RAM. |
| 1-3-4-1 | Test 512 base address lines. |
| 1-3-4-3 | Test 512K base memory. |
| 1-4-1-3 | Test CPU bus-clock frequency. |
| 1-4-2-4 | Reinitialize the chipset. |
| 1-4-3-1 | Shadow system BIOS ROM. |
| 1-4-3-2 | Reinitialize the cache. |
| 1-4-3-3 | Autosize cache. |
| 1-4-4-1 | Configure advanced chipset registers. |
| 1-4-4-2 | Load alternate registers with CMOS values. |
| 2-1-1-1 | Set Initial CPU speed. |
| 2-1-1-3 | Initialize interrupt vectors. |
| 2-1-2-1 | Initialize BIOS interrupts. |
| 2-1-2-3 | Check ROM copyright notice. |
| 2-1-2-4 | Initialize manager for PCI Options ROMs. |
| 2-1-3-1 | Check video configuration against CMOS. |
| 2-1-3-2 | Initialize PCI bus and devices. |
| 2-1-3-3 | Initialize all video adapters in system. |
| 2-1-4-1 | Shadow video BIOS ROM. |
| 2-1-4-3 | Display copyright notice. |
| 2-2-1-1 | Display CPU type and speed. |
| 2-2-1-3 | Test keyboard. |
| 2-2-2-1 | Set key click if enabled. |
| 2-2-2-3 | 56 Enable keyboard. |
| 2-2-3-1 | Test for unexpected interrupts. |
| 2-2-3-3 | Display prompt "Press F2 to enter SETUP". |
| 2-2-4-1 | Test RAM between 512 and 640k. |
| 2-3-1-1 | Test expanded memory. |
| 2-3-1-3 | Test extended memory address lines. |
| 2-3-2-1 | Jump to UserPatch1. |
| 2-3-2-3 | Configure advanced cache registers. |
| 2-3-3-1 | Enable external and CPU caches. |
| 2-3-3-3 | Display external cache size. |
| 2-3-4-1 | Display shadow message. |
| 2-3-4-3 | Display non-disposable segments. |
| 2-4-1-1 | Display error messages. |
| 2-4-1-3 | Check for configuration errors. |
| 2-4-2-1 | Test real-time clock. |
| 2-4-2-3 | Check for keyboard errors |
| 2-4-4-1 | Set up hardware interrupts vectors. |
| 2-4-4-3 | Test coprocessor if present. |
| 3-1-1-1 | Disable onboard I/O ports. |
| 3-1-1-3 | Detect and install external RS232 ports. |
| 3-1-2-1 | Detect and install external parallel ports. |
| 3-1-2-3 | Re-initialize onboard I/O ports. |
| 3-1-3-1 | Initialize BIOS Data Area. |
| 3-1-3-3 | Initialize Extended BIOS Data Area. |
| 3-1-4-1 | Initialize floppy controller. |
| 3-2-1-1 | Initialize hard-disk controller. |
| 3-2-1-2 | Initialize local-bus hard-disk controller. |
| 3-2-1-3 | Jump to UserPatch2. |
| 3-2-2-1 | Disable A20 address line. |
| 3-2-2-3 | Clear huge ES segment register. |
| 3-2-3-1 | Search for option ROMs. |
| 3-2-3-3 | Shadow option ROMs. |
| 3-2-4-1 | Set up Power Management. |
| 3-2-4-3 | Enable hardware interrupts. |
| 3-3-1-1 | Set time of day. |
| 3-3-1-3 | Check key lock. |
| 3-3-3-1 | Erase F2 prompt. |
| 3-3-3-3 | Scan for F2 key stroke. |
| 3-3-4-1 | Enter SETUP. |
| 3-3-4-3 | Clear in-POST flag. |
| 3-4-1-1 | Check for errors |
| 3-4-1-3 | POST done--prepare to boot operating system. |
| 3-4-2-1 | One beep. |
| 3-4-2-3 | Check password (optional). |
| 3-4-3-1 | Clear global descriptor table. |
| 3-4-4-1 | Clear parity checkers. |
| 3-4-4-3 | Clear screen (optional). |
| 3-4-4-4 | Check virus and backup reminders. |
| 4-1-1-1 | Try to boot with INT 19. |
| 4-2-1-1 | Interrupt handler error. |
| 4-2-1-3 | Unknown interrupt error. |
| 4-2-2-1 | Pending interrupt error. |
| 4-2-2-3 | Initialize option ROM error. |
| 4-2-3-1 | Shutdown error. |
| 4-2-3-3 | Extended Block Move. |
| 4-2-4-1 | Shutdown 10 error. |
| 4-3-1-3 | Initialize the chipset. |
| 4-3-1-4 | Initialize refresh counter. |
| 4-3-2-1 | Check for Forced Flash. |
| 4-3-2-2 | Check HW status of ROM. |
| 4-3-2-3 | BIOS ROM is OK. |
| 4-3-2-4 | Do a complete RAM test. |
| 4-3-3-1 | Do OEM initialization. |
| 4-3-3-2 | Initialize interrupt controller. |
| 4-3-3-3 | Read in bootstrap code. |
| 4-3-3-4 | Initialize all vectors. |
| 4-3-4-1 | Boot the Flash program. |
| 4-3-4-2 | Initialize the boot device. |
| 4-3-4-3 | Boot code was read OK. |