Home > Articles

  • Print
  • + Share This

How the BIOS Reports Errors

The BIOS will use three methods for reporting errors: beep codes, error/status codes, and onscreen messages. Error/status codes must be read with a special interface board, whereas the others require no special equipment.

BIOS Beep Codes and Their Purposes

Virtually all systems make a polite "beep" noise when started, but most systems have a special series of beep codes that serve the following purposes.

Beeps alert you to serious system problems, many of which can prevent your system from even starting (a so-called fatal error) or from working to its full potential (a so-called non-fatal error).

Because most fatal and many non-fatal errors take place before the video subsystem is initialized (or might indicate the video isn't working), beeps can be used to determine the cause of the problem.

A system that can't start and is reporting a problem with beep codes will give the code once and then halt. To hear the code again, restart the computer.

Use the following tables of beep codes to determine why your system will not start. To solve the problem reported by the beep codes, repair or replace the device listed in the description. If your repair or replacement has solved the problem, the beep code will no longer sound when you restart the system.

For errors involving removable devices (socketed chips, memory, or video), an easy fix is to remove and replace the item because a device that's not securely in its socket will cause the test to fail.

NOTE

For an exhaustive list of BIOS codes, beep codes, and error messages, see the CD accompanying Upgrading and Repairing PCs, 12th Edition.

AMI BIOS Beep Codes

NOTE

AMI BIOS beep codes used by permission of American Megatrends, Inc.

Beeps

Error Message

Description

1

DRAM Refresh Failure

The memory refresh circuitry on the motherboard is faulty.

2

Parity Error

A parity error occurred in system memory.

3

Base 64KB (First Bank) Memory Failure

Memory failure in the first bank of memory.

4

System Timer Failure

Memory failure in the first bank of memory, or Timer 1 on the motherboard is not functioning.

5

Processor Error

The processor on the motherboard generated an error.

6

Keyboard Controller Gate A20 Failure

The keyboard controller might be bad. The BIOS cannot switch to protected mode.

7

Virtual Mode Processor Exception Interrupt Error

The processor generated an exception interrupt.

8

Display Memory Read/Write Error

The system video adapter is either missing or its memory is faulty.

9

ROM Checksum Error

ROM checksum value does not match the value encoded in BIOS.

10

CMOS Shutdown Register Read/Write Error

The shutdown register for CMOS RAM failed.

11

Cache Error/L2 Cache Bad

The L2 cache is faulty.

1 long, 3 short

Conventional/extended memory failure

The motherboard memory is faulty.

1 long, 8 short

Display/retrace test failed

The video card is faulty; try reseating or moving to a different slot.


Award BIOS Beep Codes

Currently only one beep code exists in the Award BIOS. A single long beep followed by two short beeps indicates that a video error has occurred and the BIOS cannot initialize the video screen to display any additional information.

Phoenix BIOS Beep Codes

The following beep codes are for the current version of Phoenix BIOS, version 4.0, release 6. Other versions will have somewhat different beeps and Port 80h codes. To view the Port 80h codes, you will need a POST diagnostics card with a two-digit LED readout, available from many sources for diagnostic tools. I recommend a PCI-based POST card because ISA slots are becoming obsolete.

NOTE

Phoenix BIOS beep codes used by permission of Phoenix Technologies, Ltd.

Beeps

Port 80h Code

Explanation

1-2-2-3

16h

BIOS ROM checksum

1-3-1-1

20h

Test DRAM refresh

1-3-1-3

22h

Test keyboard controller

1-3-3-1

28h

Autosize DRAM

1-3-3-2

29h

Initialize POST memory manager

1-3-3-3

2Ah

Clear 512KB base RAM

1-3-4-1

2Ch

RAM failure on address line xxxx

1-3-4-3

2Eh

RAM failure on data bits xxxx of low byte of memory bus

1-4-1-1

30h

RAM failure on data bits xxxx of high byte of memory bus

2-1-2-2

45h

POST device initialization

2-1-2-3

46h

Check ROM copyright notice

2-2-3-1

58h

Test for unexpected interrupts

2-2-4-1

5Ch

Test RAM between 512KB and 640KB

1-2

98h

Search for option ROMs; one long, two short beeps on checksum failure

1

B4h

One short beep before boot


IBM BIOS Beep and Alphanumeric Error Codes

After completing the power on self test (POST), an audio code indicates either a normal condition or that one of several errors has occurred.

NOTE

IBM BIOS and alphanumeric error codes used by permission of IBM.

Audio Code

Sound Graph

Description

1 short beep

 

Normal POST—system okay

2 short beeps

 

POST error—error code on display

No beep

 

Power supply, system board

Continuous beep

—————

Power supply, system board

Repeating short beeps

 

Power supply, system board

1 long, 1 short beep

-

System board

1 long, 2 short beeps

-

Video adapter (MDA/CGA)

1 long, 3 short beeps

-

Video adapter (EGA/VGA)

3 long beeps

- - -

3270 keyboard card


Microid Research Beep Codes

The MR BIOS generates patterns of high and low beeps to signal an error condition.

The following beep codes are for the current and recent versions (3.x) of the MR BIOS.

NOTE

MR BIOS beep codes used by permission of Phoenix Technologies, Ltd.

Port 80h Code

Beep Codes2

Error Messages

03h

LH-LLL

ROM-BIOS Checksum Failure

04h

LH-HLL

DMA Page Register Failure

05h

LH-LHL

Keyboard Controller Selftest Failure

08h

LH-HHL

Memory Refresh Circuitry Failure

09h

LH-LLH

Master (16-bit) DMA Controller Failure

09h

LH-HLH

Slave (8-bit) DMA Controller Failure

0Ah

LH-LLLL

Base 64KB Pattern Test Failure

0Ah

LH-HLLL

Base 64KB Parity Circuitry Failure

0Ah

LH-LHLL

Base 64KB Parity Error

0Ah

LH-HHLL

Base 64KB Data Bus Failure

0Ah

LH-LLHL

Base 64KB Address Bus Failure

0Ah

LH-HLHL

Base 64KB Block Access Read Failure

0Ah

LH-LHHL

Base 64KB Block Access Read/Write Failure

0Bh

LH-HHHL

Master 8259 (Port 21) Failure

0Bh

LH-LLLH

Slave 8259 (Port A1) Failure

0Ch

LH-HLLH

Master 8259 (Port 20) Interrupt Address Error

0Ch

LH-LHLH

Slave 8259 (Port A0) Interrupt Address Error

0Ch

LH-HHLH

8259 (Port 20/A0) Interrupt Address Error

0Ch

LH-LLHH

Master 8259 (Port 20) Stuck Interrupt Error

0Ch

LH-HLHH

Slave 8259 (Port A0) Stuck Interrupt Error

0Ch

LH-LHHH

System Timer 8254 CH0/IRQ 0 Interrupt Failure

0Dh

LH-HHHH

8254 Channel 0 (System Timer) Failure

0Eh

LH-LLLLH

8254 Channel 2 (Speaker) Failure

0Eh

LH-HLLLH

8254 OUT2 (Speaker Detect) Failure

0Fh

LH-LHLLH

CMOS RAM Read/Write Test Failure

0Fh

LH-HHLLH

RTC Periodic Interrupt/IRQ 8 Failure

10h

LH-LLHLH

Video ROM Checksum Failure at Address XXXX, Mono Card Memory Error at Address XXXX, Mono Card Memory Address Line Error at Address XXXX, Color Graphics Card Memory Error at Address XXXX, Color Graphics Card Address Line Error at Address XXXX

11h

none

Real Time Clock (RTC) Battery is Discharged

11h

none

Battery Backed Memory (CMOS) is Corrupt

12h

LH-HLHLH

Keyboard Controller Failure

14h

LH-LHHLH

Memory Parity Error_18h_19h

14h

LH-HHHLH

I/O Channel Error_18h_19h

14h18h19h

none

RAM Pattern Test Failed at XXXX, Parity Circuit Failure in Bank XXXX, Data Bus Test Failed: Address XXXX, Address Line Test Failed at XXXX, Block Access Read Failure at Address XXXX, Block Access Read/Write Failure: Address XXXX, Banks Decode to Same Location: XXXX and YYYY

12h15h

none

Keyboard Error—Stuck Key Keyboard Failure or no Keyboard Present

17h

LH-LLLHH

A20 Test Failure Due to 8042 Timeout

17h

LH-HLLHH

A20 Gate Stuck in Disabled State (A20=0)

17h

none

A20 Gate Stuck in Asserted State (A20 Follows CPU)

1Ah

LH-LHLHH

Real Time Clock (RTC) is Not Updating

1Ah

none

Real Time Clock (RTC) Settings are Invalid

1Eh

none

Disk CMOS Configuration is Invalid, Disk Controller Failure, Disk Drive A: Failure, Disk Drive B: Failure

1Fh

none

Fixed Disk CMOS Configuration is Invalid, Fixed Disk C:(80) Failure, Fixed Disk D:(81) Failure, Please Wait for Fixed Disk to Spin Up

20h

none

Fixed Disk, Disk, Serial Port, Parallel Port, Video, Memory, or Numeric Coprocessor Configuration Change

21h

none

System Key is in Locked Position—Turn Key to Unlocked Position

29h

none

Adapter ROM Checksum Failure at Address XXXX

  1. Note for beep codes: L=low tone and H=high tone
  • + Share This
  • 🔖 Save To Your Account

Related Resources

There are currently no related titles. Please check back later.