Beep Codes

If you are ever in the unpleasant situation where your system simply beeps when it should be starting up, this list may help guide you toward the problem. You'll need to know your BIOS manufacturer... This can be found on the screen when the system used to boot up, or as an EEPROM chip on the mainboard. This chip is about 1/2 inch by 2 inches, socketed, and has a shiny label on it that will list the manufacturer. Alternatively, you could just go through the list one by one until you find a matching code, although it won't be any fun.

These codes are fairly standardized, but not universal - they should be used as a basis for beginning troubleshooting. They are not enough by themselves to provide a diagnosis. Consult a qualified technitian if you have any questions or before doing anything rash... Some likely sources of failures are given in parantheses; These are the most likely and intended for those that aren't sure what the given meaning means.

Key: L=Long beep S=Short beep P=Pause 2L=Two Long Beeps x=anything but a pause


Beep CodeMeaning
SNormal, system passes Power On Self Test (POST)
2SPOST error, reference error code on screen.
NonePower problem, loose card, or short circuit.
Solid TonePower problem, loose card, or short circuit.
Repeating SPower problem, loose card, or short circuit.
LSSystem board failure
L2SMonochrome or CGA card failure
L3SEGA card failure
3LKeyboard error


Beep CodeMeaning
SDRAM refresh failure
2SParity failure
3SFailure in first 64k of RAM
4SSystem timer failure (bad mainboard)
5SProcessor failure
6SKeyboard controller failure (generally bad mainboard)
7SVirtual mode exception (bad mainboard or CPU)
8SDisplay memory failure (bad video card)
9SROM checksum failure (bad mainboard)
L3SRam failure
L8SBad video card

Award BIOS

Beep CodeMeaning
SNormal, system passes POST
L2SVideo failure
2SNon-fatal error (ie stuck key, no mouse, etc)
L3SKeyboard controller failure (generally bad mainboard)

Phoenix BIOS

Beep CodeMeaning
SPSP3SCMOS failure (bad mainboard)
SPSP4SROM checksum failure (generally bad mainboard)
SP2SPSPIT failure (bad mainboard)
SP2SP2SDMA failure (bad mainboard or card)
SP2SP3SDMA failure (bad mainboard or card)
SP3SPSRAM refresh failure
SP3SP3SRAM failure in first 64k
SP4SP2SRAM parity failure in first 64k
SP4SP3SFail-Safe Timer (EISA systems only)
SP4SP4SSoftware NMI port failure (EISA systems only)
2SPxPxRAM failure in first 64k
3SPSPSSlave DMA register failure (bad mainboard)
3SPSP2SMaster DMA register failure (bad mainboard)
3SPSP3SMaster interrupt mask register failure (bad mainboard)
3SPSP4SSlave interrupt mask register failure (bad mainboard)
3SP2SP4SKeyboard controller failure (generally bad mainboard)
3SP3SP4SVideo memory failure (bad video card)
3SP4SP2SVideo retrace failure (bad video card)
4SP2SPSTimer failure (bad mainboard)
4SP2SP2SShutdown failure
4SP2SP3SGate A20 failure (bad mainboard or RAM)
4SP2SP4SUnexpected interrupt in protected mode
4SP3SPSRAM failure above 64k
4SP3SP2SPIT channel 2 failure (bad mainboard)
4SP3SP4SRealtime clock failure (bad mainboard or battery)
4SP4SPSSerial port failure
4SP4SP2SParallel port failure
4SP4SP3SMath co-processor failure