BIOS Beep POST Codes

Ever found yourself standing next to a PC that won’t boot and emits all kinds of short or long beeps. Me too. Here’s a list of what these beeps might mean.

Please note that because motherboard manufacturers often modify the code bought from these companies the beeps might mean something else.


BeepsError MessageDescription
1long, 2 shortVideo adapter errorEither video adapter is bad or is not seated properly. Also, check to ensure the monitor cable is connected properly.
Repeating (endless loop)Memory errorCheck for improperly seated or missing memory.
1long, 3shortNo video card or bad video RAMReseat or replace the video card.
High frequency beeeps while runningOverheated CPUCheck the CPU fan for proper operation. Check the case for proper air flow.
Repeating High/LowCPUEither the CPU is not seated properly or the CPU is damaged. May also be due to excess heat. Check the CPU fan or BIOS settings for proper fan speed.


Beep CodeDescriptions
1 shortDRAM refresh failure
2 shortParity circuit failure
3 shortBase 64K RAM failure
4 shortSystem timer failure
5 shortProcess failure
6 shortKeyboard controller Gate A20 error
7 shortVirtual mode exception error
8 shortDisplay memory Read/Write test failure
9 shortROM BIOS checksum failure
10 shortCMOS shutdown Read/Write error
11 shortCache Memory error
1 long, 3 shortConventional/Extended memory failure
1 long, 8 shortDisplay/Retrace test failed


BeepsError MessageDescriptionResolution
1Refresh FailureThe memory refresh circuitry is faulty.Reseat the memory SIMMs. If the system still beeps, replace the memory.
2Parity ErrorParity error in the base memory (the first 64 KB block) of memory.Reseat the memory SIMMs. If the system still beeps, replace the memory.
3Base 64 KB Memory FailureMemory failure in first 64 KB.Reseat the memory SIMMs. If the system still beeps, replace the memory.
4Timer Not OperationalA memory failure in the first 64 KB of memory, or Timer 1 is not functioning.The motherboard must be replaced.
5Processor error 8042 - Gate A20 FailureThe CPU generated an error.The motherboard must be replaced.
68042 - Gate A20 Failure Processor Exception Interrupt ErrorCannot switch to protected mode.Try a different keyboard, or replace the keyboard fuse, if the keyboard has one.
7Processor Exception Interrupt ErrorThe CPU on the CPU Card generated an exception interrupt.The motherboard must be replaced.
8Display Memory Read/Write ErrorThe 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.
9ROM Checksum ErrorThe 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.
10CMOS Shutdown Register Read/Write ErrorThe shutdown register for CMOS RAM has failed.The motherboard must be replaced.
11Cache memory bad - do not enable cacheThe 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 CodeDescriptions
No BeepsNo Power, Loose Card, or Short.
1 Short BeepNormal POST, computer is ok.
2 Short BeepPOST error, review screen for error code.
Continuous BeepNo Power, Loose Card, or Short.
Repeating Short BeepNo Power, Loose Card, or Short.
One Long and one Short BeepMotherboard issue.
One Long and Two short BeepsVideo (Mono/CGA Display Circuitry) issue.
One Long and Three Short Beeps.Video (EGA) Display Circuitry.
Three Long BeepsKeyboard / Keyboard card error.
One Beep, Blank or Incorrect DisplayVideo Display Circuitry.


Error Tone. (two sets of different tones)Problem with logic board or SCSI bus.
Startup tone, drive spins, no videoProblem with video controller.
Powers on, no tone.Logic board problem.
High Tone, four higher tones.Problem with SIMM.



Beep CodeDescriptions / What to Check
1-1-1-3Verify Real Mode.
1-1-2-1Get CPU type.
1-1-2-3Initialize system hardware.
1-1-3-1Initialize chipset registers with initial POST values.
1-1-3-2Set in POST flag.
1-1-3-3Initialize CPU registers.
1-1-4-1Initialize cache to initial POST values.
1-1-4-3Initialize I/O.
1-2-1-1Initialize Power Management.
1-2-1-2Load alternate registers with initial POST values.
1-2-1-3Jump to UserPatch0.
1-2-2-1Initialize keyboard controller.
1-2-2-3BIOS ROM checksum.
1-2-3-18254 timer initialization.
1-2-3-38237 DMA controller initialization.
1-2-4-1Reset Programmable Interrupt Controller.
1-3-1-1Test DRAM refresh.
1-3-1-3Test 8742 Keyboard Controller.
1-3-2-1Set ES segment to register to 4 GB.
1-3-3-128 Autosize DRAM.
1-3-3-3Clear 512K base RAM.
1-3-4-1Test 512 base address lines.
1-3-4-3Test 512K base memory.
1-4-1-3Test CPU bus-clock frequency.
1-4-2-4Reinitialize the chipset.
1-4-3-1Shadow system BIOS ROM.
1-4-3-2Reinitialize the cache.
1-4-3-3Autosize cache.
1-4-4-1Configure advanced chipset registers.
1-4-4-2Load alternate registers with CMOS values.
2-1-1-1Set Initial CPU speed.
2-1-1-3Initialize interrupt vectors.
2-1-2-1Initialize BIOS interrupts.
2-1-2-3Check ROM copyright notice.
2-1-2-4Initialize manager for PCI Options ROMs.
2-1-3-1Check video configuration against CMOS.
2-1-3-2Initialize PCI bus and devices.
2-1-3-3Initialize all video adapters in system.
2-1-4-1Shadow video BIOS ROM.
2-1-4-3Display copyright notice.
2-2-1-1Display CPU type and speed.
2-2-1-3Test keyboard.
2-2-2-1Set key click if enabled.
2-2-2-356 Enable keyboard.
2-2-3-1Test for unexpected interrupts.
2-2-3-3Display prompt “Press F2 to enter SETUP”.
2-2-4-1Test RAM between 512 and 640k.
2-3-1-1Test expanded memory.
2-3-1-3Test extended memory address lines.
2-3-2-1Jump to UserPatch1.
2-3-2-3Configure advanced cache registers.
2-3-3-1Enable external and CPU caches.
2-3-3-3Display external cache size.
2-3-4-1Display shadow message.
2-3-4-3Display non-disposable segments.
2-4-1-1Display error messages.
2-4-1-3Check for configuration errors.
2-4-2-1Test real-time clock.
2-4-2-3Check for keyboard errors
2-4-4-1Set up hardware interrupts vectors.
2-4-4-3Test coprocessor if present.
3-1-1-1Disable onboard I/O ports.
3-1-1-3Detect and install external RS232 ports.
3-1-2-1Detect and install external parallel ports.
3-1-2-3Re-initialize onboard I/O ports.
3-1-3-1Initialize BIOS Data Area.
3-1-3-3Initialize Extended BIOS Data Area.
3-1-4-1Initialize floppy controller.
3-2-1-1Initialize hard-disk controller.
3-2-1-2Initialize local-bus hard-disk controller.
3-2-1-3Jump to UserPatch2.
3-2-2-1Disable A20 address line.
3-2-2-3Clear huge ES segment register.
3-2-3-1Search for option ROMs.
3-2-3-3Shadow option ROMs.
3-2-4-1Set up Power Management.
3-2-4-3Enable hardware interrupts.
3-3-1-1Set time of day.
3-3-1-3Check key lock.
3-3-3-1Erase F2 prompt.
3-3-3-3Scan for F2 key stroke.
3-3-4-1Enter SETUP.
3-3-4-3Clear in-POST flag.
3-4-1-1Check for errors
3-4-1-3POST done-prepare to boot operating system.
3-4-2-1One beep.
3-4-2-3Check password (optional).
3-4-3-1Clear global descriptor table.
3-4-4-1Clear parity checkers.
3-4-4-3Clear screen (optional).
3-4-4-4Check virus and backup reminders.
4-1-1-1Try to boot with INT 19.
4-2-1-1Interrupt handler error.
4-2-1-3Unknown interrupt error.
4-2-2-1Pending interrupt error.
4-2-2-3Initialize option ROM error.
4-2-3-1Shutdown error.
4-2-3-3Extended Block Move.
4-2-4-1Shutdown 10 error.
4-3-1-3Initialize the chipset.
4-3-1-4Initialize refresh counter.
4-3-2-1Check for Forced Flash.
4-3-2-2Check HW status of ROM.
4-3-2-3BIOS ROM is OK.
4-3-2-4Do a complete RAM test.
4-3-3-1Do OEM initialization.
4-3-3-2Initialize interrupt controller.
4-3-3-3Read in bootstrap code.
4-3-3-4Initialize all vectors.
4-3-4-1Boot the Flash program.
4-3-4-2Initialize the boot device.
4-3-4-3Boot code was read OK.