BIOS Beep POST Codes

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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.


Beeps Error Message Description
1long, 2 short Video adapter error Either video adapter is bad or is not seated properly. Also, check to ensure the monitor cable is connected properly.
Repeating (endless loop) Memory error Check for improperly seated or missing memory.
1long, 3short No video card or bad video RAM Reseat or replace the video card.
High frequency beeeps while running Overheated CPU Check the CPU fan for proper operation. Check the case for proper air flow.
Repeating High/Low CPU Either 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 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


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.


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



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.