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A Reference Guide to the Precision Workstation Diagnostic Indicators

Summary: This article is a reference guide to the various methods used on Dell Precision workstations to diagnose No POST faults during startup.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Instructions

Dell Precision Workstation Desktops have a long history of integrated diagnostic indicators. These can be audible beeps, power buttons that display different states and colors, specific diagnostics LEDs or a combination of them all. So that they can indicate at which point during the Power On Self-Test (POST) a device is having issues.

The following article is a reference guide to the codes available on each model and what those codes mean. These change through the various models and years. These indicators are merely a starting point for narrowing down any troubleshooting to be carried out to identify the cause of your current issue. You can use this as a starting place to narrow down the proper troubleshooting guide required. Alternatively, you can contact technical support for further help and they require these indicators as well.

Note: For all the tables below, remember that the diagnostic LEDs only serve as an indicator of the progress through the POST process. These LEDs do not indicate the problem that caused the POST routine to stop.
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Note: The Precision 36x0 series of Workstation Towers have an additional feature that is not seen on any other desktop computers. These particular towers can run on into the enhanced Pre-Boot System Assessment (ePSA) diagnostics once the POST process completes. The power LED stops blinking Amber and White for a POST error, and instead the LED blinks a four-digit Amber code. The new error code matches the last four digits of the ePSA error code when it detects an error that was not found during POST. You can match the four digit ePSA error in the following article:

The Power Button state now gives a new blink and color shift pattern. It uses both Amber, and White power LED flashes to indicate where it has a problem. You can identify these desktops by the fact that there is no Diagnostics LED block on the front of the unit.

2017 to present Precision Workstations

Power Button LEDs

Power Button LED State Description
Power LED off Off The power is Off. LED is blank.
Power LED blinking amber Blinking Amber Initial State of LED when you switch it on. See the table below for Blinking Amber pattern diagnostic suggestions and possible failures.
Power LED solid amber Solid Amber The second state of the LED when you switch it on indicates that the POWER_GOOD signal is active. It also indicates that the power supply is fine.
Power LED blinking white Blinking White The desktop is in a low-power state, either S1 or S3. This does not indicate a fault condition.
Power LED solid white Solid White The device is in the S0 state. This is the normal power states of a functioning machine. The BIOS turns the LED to this state to indicate it has started fetching op-codes.

Diagnostic Indicator Table

State State Name Power Light:
Amber Blinking		 Amber Blinking Pattern Problem Description Suggested Resolution
- - 1, 1 One amber blink followed by a short pause, one white blink, a long pause, then repeats Bad Motherboard
  • Contact Tech Support to troubleshoot the motherboard
- - 1, 2 One amber blink followed by a short pause, two white blinks, a long pause, then repeats. Bad Motherboard, Power Supply, or Power Supply cabling
  • If you can assist to troubleshoot, narrow down the issue with the Power Supply Unit (PSU) BIST Test, reseat cable.
  • If nothing works, contact Tech Support
- - 1, 3 One amber blink followed by a short pause, three white blinks, a long pause, then repeats. Bad Motherboard, Memory, or Processor
  • If you can assist to troubleshoot, narrow down the issue by reseating memory and swapping a known good memory if available.
  • If nothing works, contact Tech Support
- - 1, 4 One amber blink followed by a short pause, four white blinks, a long pause, then repeats. Bad Coin Cell Battery
  • CPU configuration activity is in progress, or a CPU Failure was detected
  • Contact Tech Support
S2 CPU 2, 1 Two amber blinks followed by a short pause, one white blinks, a long pause, then repeats. Bad Processor
  • CPU configuration activity is in progress, or a CPU failure was detected.
  • Contact Tech Support
S1 RCM 2, 2 Two amber blinks followed by a short pause, two white blinks, long pause, then repeats. BIOS ROM Failure
  • The device is in Recovery Mode.
  • Flash latest BIOS version. If the problem persists, contact Tech Support
S6 STO 2, 3 Two amber blinks followed by a short pause, three white blinks, long pause, then repeats. No Memory detected
  • If the customer can assist to troubleshoot, narrow down the issue by removing one by one memory to determine which memory failed and swapping to a known good memory if available to confirm.
  • Contact Tech Support.
S3 MEM 2, 4 Two amber blinks followed by a short pause, four white blinks, long pause, then repeats. Memory failures
  • Configuration activity for the memory subsystem is in progress. Appropriate memory modules were detected, but a memory failure has occurred.
  • If you can assist to troubleshoot, narrow down the issue with reseating memory and swapping a known good memory if available.
  • If nothing works, contact Tech Support.
S8 MEM 2, 5 Two amber blinks followed by a short pause, five white blinks, long pause, then repeats. Invalid memory is installed.
  • Configuration activity for the memory subsystem is in progress. Appropriate memory modules were detected but appear to be incompatible or in an invalid configuration.
  • If you can assist to troubleshoot, narrow down the issue with reseating memory and swapping a known good memory if available.
  • If nothing works, contact Tech Support.
S9 MBF 2, 6 Two amber blinks followed by a short pause, six white blinks, long pause, then repeats. Motherboard: Chipset
  • A motherboard failure is detected.
  • If the customer can assist to troubleshoot, narrow down the issue by removing components one by one to determine which component failed.
  • Contact Tech Support.
- - 3, 1 Three amber blinks followed by a short pause, one white blink, a long pause, then repeats. RTC Power Failure
  • If the customer can assist to troubleshoot, narrow down the issue by swapping for a known good (working) CMOS Battery.
  • Contact Tech Support.
S4 PCI 3, 2 Three amber blinks followed by a short pause, two white blinks, long pause, then repeats. PCI Device or Video
  • PCI device configuration activity is in progress, or PCI device failure was detected.
  • If you can assist to troubleshoot, narrow down the issue by reseating PCI card and removing one by one to determine which card failed.
  • Contact Tech Support.
- - 3, 3 Three amber blinks followed by a short pause, three white blinks, long pause, then repeats. BIOS Recovery 1
  • The device is in recovery mode
  • Flash with latest BIOS revision and Contact Tech Support if still not resolved
- - 3, 4 Three amber blinks followed by a short pause, four white blinks, long pause, then repeats. BIOS Recovery 2
  • The device is in recovery mode
  • Flash with latest BIOS revision and Contact Tech Support if still not resolved
- - 4, 1 Four amber blinks followed by a short pause, one white blink, a long pause, then repeats. CPU Configuration or CPU Failure
  • If you can assist to troubleshoot, narrow down the issue by removing parts until the minimum required to POST.
  • Contact Tech Support.
- - 4, 2 Four amber blinks followed by a short pause, two white blinks, a long pause, then repeats. Generic Post Video Error
  • If you can assist to troubleshoot, narrow down the issue by switching between onboard and a discrete video card to determine where the fault falls.
  • Contact Tech Support.
- - 4, 3 Four amber blinks followed by a short pause, three white blinks, long pause, then repeats. Bad Memory
  • If you can assist to troubleshoot, narrow down the issue by trying memory DIMMs individually in each slot and test with known good (working) memory to determine where the fault lies.
  • Contact Tech Support.
- - 4, 4 Four amber blinks followed by a short pause, four white blinks, long pause, then repeats. Riser Board Issue
  • If you can assist to troubleshoot, narrow down the issue by removing parts until the minimum required to POST to determine the point of failure.
  • Contact Tech Support.
- - 4, 5 Four amber blinks followed by a short pause, five white blinks, long pause, then repeats. PCIe Add-in Card Population Issue
  • If you can assist to troubleshoot, narrow down the issue by primary video card only.
  • Contact Tech Support.
- - 4, 6 Four amber blinks followed by a short pause, six white blinks, long pause, then repeats. RAID Volume degraded
  • RAID volume is degraded.
  • If possible, boot to the F12 menu to enter the device configuration tab and rebuild the RAID volume.
  • Contact Tech Support if the issue persists.
- - 4, 7 Four amber blinks followed by a short pause, seven white blinks, a long pause, then repeats. System Side cover is missing.
  • System side cover (either left or right) is missing.
  • Install the side covers and restart.
  • Contact Tech Support if not resolved.

With this series, the diagnostics indicator LEDs have been removed. Instead the Power Button state now gives a blink and color shift pattern to indicate where it had a problem. You can identify these desktops by the fact that there is no Diagnostics LED block on the front of the unit.

2014 to 2017 Precision series

Power Button LEDs

Power Button LED State Description
Power LED off Off The power is Off. LED is blank.
Power LED blinking amber Blinking Amber Initial State of the LED at switching the device on. See the table below for Blinking Amber pattern diagnostic suggestions and possible failures.
Power LED solid amber Solid Amber The second state of the LED at switching the device on indicates that the POWER_GOOD signal is active. It also indicates that the power supply is fine.
Power LED blinking white Blinking White The device is in a low-power state, either S1 or S3. This does not indicate a fault condition.
Power LED solid white Solid White The device is in the S0 state. This is the normal power states of a functioning machine. The BIOS turns the LED to this state to indicate it has started fetching op-codes.

Diagnostic Indicator Table

State State Name Power Light:
Amber Blinking		 Amber Blinking Pattern Problem Description Suggested Resolution
- - 2, 1 2 blinks followed by a short pause, one blink, long pause, then repeats. Bad Motherboard
  • Contact Tech Support to troubleshoot the motherboard
- - 2, 2 2 blinks followed by a short pause, 2 blinks, long pause, then repeats. Bad Motherboard, Power Supply, or Power Supply cabling
  • If you can assist to troubleshoot, narrow down the issue with PSU BIST Test, reseat the cable.
  • If nothing works, contact Tech Support
- - 2, 3 2 blinks followed by a short pause, 3 blinks, long pause, then repeats. Bad Motherboard, Memory, or Processor
  • If you can assist to troubleshoot, narrow down the issue by reseating memory and swapping a known good memory if available.
  • If nothing works, contact Tech Support
- - 2, 4 2 blinks followed by a short pause, 4 blinks, long pause, then repeats. Bad coin-cell battery
  • If you can assist to troubleshoot, narrow down the issue by swapping a known good coin-cell battery if available.
  • If nothing works, contact Tech Support
S1 RCM 2, 5 2 blinks followed by a short pause, 5 blinks, long pause, then repeats. BIOS Checksum Failure
  • The device is in Recovery Mode.
  • Flash latest BIOS version. If the problem persists, contact Tech Support
S2 CPU 2, 6 2 blinks followed by a short pause, 6 blinks, long pause, then repeats. Bad Processor
  • CPU configuration activity is in progress, or a CPU failure was detected.
  • Contact Tech Support
S3 MEM 2, 7 2 blinks followed by a short pause, 7 blinks, long pause, then repeats. Memory failures
  • Configuration activity for the memory subsystem is in progress. Appropriate memory modules were detected, but a memory failure has occurred.
  • If you can assist to troubleshoot, narrow down the issue with reseating memory and swapping a known good memory if available.
  • If nothing works, contact Tech Support.
S4 PCI 3, 1 3 blinks followed by a short pause, one blink, long pause, then repeats. PCI Device or Video subsystem failures
  • PCI device configuration activity is in progress, or PCI device failure was detected.
  • If you can assist to troubleshoot, narrow down the issue by reseating PCI card and removing one by one to determine which card failed.
  • Contact Tech Support.
S5 VID 3, 2 3 blinks followed by a short pause, 2 blinks, long pause, then repeats. Video Subsystem failure
  • The configuration activity for the video subsystem is in progress or there is a video subsystem failure.
  • If a customer can assist to troubleshoot, narrow down the issue by removing one by one to determine which card failed.
  • Contact Tech Support.
S6 STO 3, 3 3 blinks followed by a short pause, 3 blinks, long pause, then repeats. No Memory detected
  • If the customer can assist to troubleshoot, narrow down the issue by removing one by one memory to determine which memory failed and swapping to a known good memory if available to confirm.
  • Contact Tech Support.
S7 USB 3, 4 3 blinks followed by a short pause, 4 blinks, long pause, then repeats. Storage Subsystem failure
  • It is possible that device configuration for the storage is in progress or storage subsystem failure.
  • If you can assist to troubleshoot, narrow down the issue by removing one by one the storages on the motherboard to determine which storage device failed.
  • Contact Tech Support.
S8 MEM 3, 5 3 blinks followed by a short pause, 5 blinks, long pause, then repeats. Memory configuration or incompatible error
  • Configuration activity for the memory subsystem is in progress. No memory modules were detected.
  • If a customer can assist to troubleshoot, narrow down the issue by removing one by one the memory on the motherboard to determine which memory failed. Also, combining the configuration to validate the appropriate combination.
  • Contact Tech Support
S9 MBF 3, 6 3 blinks followed by a short pause, 6 blinks, long pause, then repeats. System board failure
  • A fatal motherboard failure is detected.
  • If a customer can assist to troubleshoot, narrow down the issue by removing one by one the component on the motherboard to determine which component failed.
  • If you identified any of the components failed, replace the component.
  • Contact Tech Support
S10 MEM 3, 7 3 blinks followed by a short pause, 7 blinks, long pause, then repeats. Possible memory failure
  • Configuration activity for the memory subsystem is in progress. Memory modules have been detected but appear to be incompatible or in an invalid configuration.
  • If a customer can assist to troubleshoot, narrow down the issue by removing one by one the memory on the motherboard to determine which memory failed.
  • Contact Tech Support.

With this series, the Diagnostic LEDs changed to include a combination of the Power button LED state and the diagnostic LED indicators. The Diagnostic LEDs remain 1, 2, 3, 4, and placed on the front of the unit. You could identify these desktops by their flat black and recessed Grill on the front face.

2012 to 2013 Precision series

Note: There are three types of color for the Power LED: Green, Blue, or White depending on the desktop model

Power LED

Power Button LED State Description
Power LED off Off The power is Off. LED is blank.
Power LED blinking amber Blinking Amber Initial State of LED at switch-on. See the table below for Blinking Amber pattern diagnostic suggestions and possible failures.
Power LED solid amber Solid Amber The second state of the LED at switching the desktop on indicates that the POWER_GOOD signal is active. It also indicates that the power supply is fine.
Power LED blinking white Blinking White The device is in a low-power state, either S1 or S3. This does not indicate a fault condition.
Power LED solid white Solid White The device is in the S0 state. This is the normal power states of a functioning machine. The BIOS turns the LED to this state to indicate it has started fetching op-codes.

Diagnostic LEDs (Pre-Post)

Precision Diagnostic LEDs example

Note: Diagnostic LEDs can be either Green or Amber depending on the model type, but are always either off, flashing, or solid on.
State LED Pattern
(1 2 3 4 )		 LED Description Power LED State Assignment State Description
Pb0a Off Off Power LED off System Unplugged The device is not plugged into AC, PSU is not plugged into system board, or control panel not connected to system board.
Pb0b Off Off Power LED solid white ACPI S0; Normal Operation The device is on with no failures detected. This is a BIOS-controlled state and is also S0e.
Pb0c Off Off Power LED blinking white ACPI S1 Sitting in windows standby state.
Pb1 Off Off Power LED off ACPI S4 or S5 Hibernate or Soft off. System plugged in, but it is either turned off or in Windows Hibernation State.
Pb2 3 solid 3 - Solid - Reserved Reserved
Pb3 3 and 4 solid 3,4 - Solid Power LED blinking white ACPI S3 Suspend RAM to Windows Standby State.
Pb4 2 solid 2 - Solid - Reserved Reserved
Pb5 2 and 4 solid 2,4 - Solid - Reserved Reserved
Pb6 2 and 3 solid 2,3 - Solid - Reserved Reserved
Pb7 2 3 and 4 flashing on 2,3,4 - Flashing On Power LED solid amber ACPI S0, hand off to BIOS control The device is on. The BIOS is not starting. This is the transition state to POST states.
Pb8 1 solid 1 - Solid - Reserved Reserved
Pb9 1 and 4 flashing on 1,4 - Flashing On Power LED solid amber Non-System board Regulator Failure A power failure has been detected on a plug-in component such as VRM, Video Riser, or Memory Riser.
Pb10 1 and 3 flashing on 1,3 - Flashing On Power LED blinking amber PSU Failure PSU may be bad, or PSU cable may be crimped creating a short on a main power rail. (PS_ON asserted, PS_PWRGOOD not asserted)
Pb11 1 3 and 4 flashing on 1,3,4 - Flashing On Power LED solid amber PSU Cable Failure All PSU cables may not be properly connected to system board. (PS_ON asserted, missing a main power rail)
Pb12 1 and 2 flashing on 1,2 - Flashing On Power LED solid amber System board Regulator Failure A power failure has been detected in one of the onboard motherboard regulators. A failed motherboard component or by a plug-in device creating a short on a regulated power rail can cause this. (PS_ON asserted, PS_PWRGOOD asserted, SYS_PWRGOOD de-asserted)
Pb13 1 2 and 4 flashing on 1,2,4 - Flashing On Power LED off Mismatch Hardware detected a population incompatibility with a critical component such as CPU, VRM, PSU, or MEMORY RISER.
Pb14 1 2 and 3 solid 1,2,3 - Solid - Reserved Reserved
Pb15 1 2 3 4 solid 1,2,3,4 - Solid - Reserved Reserved

Diagnostic LEDs (Post)

State LED pattern
(1 2 3 4 )		 LED Description State Name State assignment State description Suggested Resolution
S0a Off Off OFF OFF The power LED is Off. No power is supplied to the device.
  • If the LEDs came on and then went off, look at troubleshooting the display and the operating system.
  • If the LEDs never came on at any point, then look into a power issue.
S0e Off Off ON Normal Operation, ACPI S0 The power LED is Solid Green, Blue, or White. The device has successfully booted and is operating.  
S1 4 solid 4 RCM The device is in Recovery Mode. BIOS checksum failure was detected, and the device is now in recovery mode.
  • Reset the BIOS and clear the NVRAM
  • If this occurred after Windows updates, check that your startup was not corrupted.
S2 3 solid 3 CPU CPU The CPU configuration activity is in progress, or a CPU failure was detected.
  • Disconnect all devices and configure the desktop down to PSU, Motherboard, and CPU
  • If the fault continues contact your technical support
  • If the fault stops, plug disconnected parts back one at a time until the fault recurs. Contact your technical support to take this further.
S3 3 and 4 solid 3,4 MEM Memory The configuration activity for the memory subsystem is in progress. Appropriate memory modules were detected, but a memory failure has occurred.
  • Remove all memory from the device, does the LED code change?
  • If it does not, contact your technical support
  • If it does, add the memory modules back one at a time until the fault recurs, test that module in another slot and contact your technical support
S4 2 solid 2 PCI PCI device PCI device configuration activity is in progress, or PCI device failure was detected.
  • Remove all devices and all internal PCI devices
  • If the fault continues contact your technical support
  • If the fault stops, add parts back one at a time until the fault recurs and contact your technical support
S5 2 and 4 solid 2,4 VID Video Card The configuration activity for the video subsystem is in progress, or the video subsystem is failing.
  • Ensure that the video cable is connected to the correct port
  • Reseat any add-in graphics cards
  • If the fault continues, remove any add-in graphics cards and test with known good monitor and video cable
  • Contact your technical support once you know which part the fault follows
S6 2 and 3 solid 2,3 STO Storage The configuration of the storage device is in progress, or the storage subsystem is failing.
  • Reseat the cables from the hard drives to the motherboard
  • If the fault continues, try substituting a known good hard drive into the device and contact your technical support
S7 2 3 and 4 solid 2,3,4 USB USB The configuration activity for the USB subsystem is in progress, or the USB subsystem is failing.
  • Remove all devices and any internal CRUs
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
S8 1 solid 1 MEM Memory The configuration activity for the memory subsystem is in progress. No memory modules are detected.
  • Reseat all memory modules
  • If the fault continues, try the memory in different slots and contact your technical support
S9 1 and 4 solid 1,4 MBF Motherboard A fatal motherboard failure is detected.
  • Contact your technical support
S10 1 and 3 solid 1,3 MEM Memory The configuration activity for the memory subsystem is in progress. Memory modules have been detected but appear to be incompatible or in an invalid configuration.
  • Reset the BIOS and clear the NVRAM and any previous errors
  • Remove all memory from the device. This includes any graphics cards. Does the LED code change?
  • If it does not, contact your technical support
  • If it does, add the parts back one at a time until the fault recurs, test that part in another slot and contact your technical support
S11 1 3 and 4 solid 1,3,4 PRV Other pre-video activity This indicates routine activity that preceded the video initialization.
  • Remove all devices and any internal CRUs
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
S12 1 and 2 solid 1,2 CFG Resource configuration The desktops resource configuration is in progress.
  • Reset the BIOS and clear the NVRAM and any previous errors
  • Remove all devices
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
S13 1 2 and 4 solid 1,2,4   Reserved This is reserved for future use. This pattern is being considered to indicate the Visual Off state on the desktop.
  • Reserved
S14 1 2 and 3 solid 1,2,3 POV Other post-video activity This indicates routine desktop activity after the video initialization.
  • Troubleshoot as per the error message on-screen
S15 1 2 3 and 4 solid 1,2,3,4 STD Boot hand off This indicates the End of the POST process. LEDs are in this state briefly as POST completes. Once the hand-off to the operating system is done, the LEDs turn off and transition to S0e state.
  • The Power On Self-Test has passed all checks
  • Troubleshoot the hard drive and the Operating System

This series had a combination of Power button LED states with the diagnostic LEDs 1, 2, 3, 4. The diagnostics LEDs are on the front of the chassis.

2010 to 2011 Precision series

Note: There are two types of color for the Power LED: Green or Blue depending on the desktop model.

Power LEDs

Off Blinking Amber Solid Amber Solid Green Blinking Green
Power LED off Power LED blinking amber Power LED solid amber Power LED solid green Power LED blinking green

Diagnostics LEDs

Light Pattern Problem
Description		 Suggested Resolution
Diagnostic LEDs Power
Button LED		  
Off Power LED off The device is either turned off or not receiving power.
  • Reseat the power cable in the power connector on the back of the device and the electrical outlet.
  • Bypass power strips, power extension cables, and other power protection devices to verify that the device turns on properly.
  • Ensure that any power strips being used to are plugged into an electrical outlet and are turned on.
  • Ensure that the electrical outlet is working by testing it with another device, such as a lamp.
  • Ensure that the main power cable and front panel cable are securely connected to the system board.
3 on Power LED off A possible system board failure has occurred.
  • Unplug the device. Allow one minute for the power to drain. Plug the device into a working electrical outlet and press the power button.
1 and 3 on Power LED blinking amber
Blinking		 A possible system board, power supply, or peripheral failure has occurred.
  • Power off the device, leaving the desktop plugged in. Press and hold the test button on the rear of the power supply unit. If the LED next to the switch illuminates, the problem may be with your system board.
  • If the LED next to the switch does not illuminate, disconnect all internal and devices, and press and hold the test button on the power supply. If it illuminates, there could be a problem with a peripheral.
  • If the LED still does not illuminate, remove the PSU connections from the system board, then press and hold the power supply button. If it illuminates, there could be a problem with the system board.
  • If the LED still does not illuminate, the problem is probably with the power supply.
1 2 and 4 on Power LED solid amber There is no CPU present.
  • Reinstall the CPU and restart the desktop. If the device still fails to boot, inspect the CPU socket for damage.
3 and 4 on Power LED solid amber Memory modules are detected, but a memory power failure has occurred.
  • If two or more memory modules are installed, remove the modules, then reinstall one module and restart the desktop. If the device starts, continue to install additional memory modules (one at a time) until you have identified a faulty module or reinstalled all modules without error. If only one memory module is installed, try moving it to a different DIMM connector and restart the device.
  • If available, install verified working memory of the same type into your desktop.
2 and 3 on Power LED solid amber A possible CPU or system board failure has occurred.
  • Replace the CPU with a known good CPU. If the desktop still fails to boot, inspect the CPU socket for damage.
2 3 and 4 on Power LED solid amber BIOS may be corrupt or missing.
  • The devices hardware is operating, but the BIOS may be corrupt or missing.
1 on Power LED solid amber A possible motherboard failure has occurred.
  • Remove all peripheral cards from the PCI and PCI-E slots and restart the desktop. If the device boots, add the peripheral cards back one by one until you find the bad one.
1 and 4 on Power LED solid amber Power connector not installed properly.
  • Reseat the 2x2 power connector from the power supply unit.
2 on Power LED solid amber Possible peripheral card or system board failure has occurred.
  • Remove all peripheral cards from the PCI and PCI-E slots and restart the device. If the desktop boots, add the peripheral cards back one by one until you find the bad one.
1 and 2 on Power LED solid amber A possible system board failure has occurred.
  • Disconnect all internal and devices, and restart the device. If the desktop boots, add the peripheral cards back one by one until you find the bad one.
  • If the problem persists, the motherboard may be bad.
1 2 and 3 on Power LED solid amber A possible coin-cell battery failure has occurred.
  • Remove the coin-cell battery for one minute, reinstall the battery, and restart.
Off Power LED solid blue The device is in a standard on condition. The diagnostic lights are not lit after the desktop successfully boots to the operating system.
  • Ensure that the display is connected and powered on.
3 on Power LED solid blue A possible processor failure has occurred.
  • Reseat the processor.
3 and 4 on Power LED solid blue Memory modules are detected, but a memory failure has occurred.
  • If two or more memory modules are installed, remove the modules (see your service manual), then reinstall one module (see your service manual and restart the device. If the desktop starts, continue to install additional memory modules (one at a time) until you have identified a faulty module or reinstalled all modules without error.
  • If available, install working memory of the same type into your desktop.
2 and 4 on Power LED solid blue A possible graphics card failure has occurred.
  • Reseat any installed graphics cards.
  • If available, install a working graphics card into your desktop.
2 and 3 on Power LED solid blue A possible floppy drive or hard drive failure has occurred.
  • Reseat all power and data cables.
2 3 and 4 on Power LED solid blue A possible USB failure has occurred.
  • Reinstall all USB devices and check all cable connections.
1 on Power LED solid blue No memory modules are detected.
  • If two or more memory modules are installed, remove the modules (see your service manual), then reinstall one module (see your service manual) and restart the device. If the desktop starts, continue to install additional memory modules (one at a time) until you have identified a faulty module or reinstalled all modules without error.
  • If available, install working memory of the same type into your desktop.
1 and 3 on Power LED solid blue Memory modules are detected, but a memory configuration or compatibility error has occurred.
  • Ensure that no special requirements for memory module or connector placement exist.
  • Ensure that the desktop supports the memory that you are using.
1 and 2 on Power LED solid blue A possible expansion card failure has occurred.
  • Determine if a conflict exists by removing an expansion card (not a graphics card) and restarting the device.
  • If the problem persists, reinstall the card you removed, then remove a different card and restart the device.
  • Repeat this process for each expansion card installed. If the device starts, troubleshoot the last card removed from the desktop for resource conflicts.
1 3 and 4 on Power LED solid blue A possible motherboard resource or hardware failure has occurred.
  • Clear CMOS.
  • Disconnect all internal and devices, and restart the device. If the desktop boots, add the peripheral cards back one by one until you find the bad one.
  • If the problem persists, the motherboard or a motherboard component may be bad.
1 2 and 3 on Power LED solid blue Another failure has occurred.
  • Ensure that all hard drive and optical drive cables are properly connected to the system board.
  • If there is an error message on the screen identifying a problem with a device (such as the floppy drive or hard drive), check the device to confirm that it is functioning properly.
  • If the operating system is attempting to boot from a device (such as the floppy drive or optical drive), check system setup to ensure that the boot sequence is correct for the devices installed on your desktop.

Dell Precision desktops have a long history of integrated diagnostic indicators. These can be audible beeps and specific diagnostics LEDs to indicate when during the Power On Self-Test (POST) a device is having issues.

These models had a block of 1, 2, 3, 4, LEDs on the front of the chassis that either lit up Green or were off. A table below is included below with what these indicated. These models were primarily Tower desktops.

Precision series prior to 2009

Diagnostic LEDs

Example of diagnostic LEDs

LED Pattern
(1 2 3 4)		 LED
Pattern		 State
Name		 State
Description		 Suggested Resolution
Off Off Off POST completes — LED time-out has occurred.
  • If the LEDs came on and then went off, look at troubleshooting the display and the operating system.
  • If the LEDs never came on at any point, then look into a power issue.
4 on 4 RCM BIOS checksum failure — Recovery mode
  • Reset the BIOS and clear the NVRAM
  • If this occurred after Windows updates, check that your startup was not corrupted.
3 on 3 CPU CPU configuration activity or failure; CPU Cache failure
  • Disconnect all devices and configure the device down to the PSU, Motherboard, and CPU
  • If the fault continues contact your technical support
  • If the fault stops, plug disconnected parts back one at a time until the fault recurs. Contact your technical support to take this further.
3 and 4 on 34 MEM Configuration activity for the memory subsystem or failure
  • Remove all memory from the device, does the LED code change?
  • If it does not, contact your technical support
  • If it does, add the memory modules back one at a time until the fault recurs, test that module in another slot and contact your technical support
2 on 2 PCI PCI device configuration or failure
  • Remove all devices and all internal PCI devices
  • If the fault continues contact your technical support
  • If the fault stops, add parts back one at a time until the fault recurs and contact your technical support
2 and 4 on 2 4 VID Video subsystem configuration or failure
  • Ensure that the video cable is connected to the correct port
  • Reseat any add-in graphics cards
  • If the fault continues, remove any add-in graphics cards and test with known good monitor and video cable
  • Contact your technical support once you know which part the fault follows
2 and 3 on 23 STO Storage device configuration or failure
  • Reseat the cables from the hard drives to the motherboard
  • If the fault continues, try substituting a known good hard drive into the desktop and contact your technical support
2 3 and 4 on 234 USB USB subsystem configuration activity or failure
  • Remove all devices and any internal CRUs
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
1 on 1   No memory detected
  • Reseat all memory modules
  • If the fault continues, try the memory in different slots and contact your technical support
1 and 4 on 1 4 MBF Fatal system board failure detected
  • Contact your technical support
1 and 3 on 1 3   Memory is detected, configuration, or compatibility error.
  • Reset the BIOS and clear the NVRAM and any previous errors
  • Remove all memory from the device, This includes any graphics cards. Does the LED code change?
  • If it does not, contact your technical support
  • If it does, add the parts back one at a time until the fault recurs, test that part in another slot and contact your technical support
1 3 and 4 on 1 34 PRV This indicates that device activity preceded the video initialization.
  • Remove all devices and any internal CRUs
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
1 and 2 on 12 CFG System resource configuration
  • Reset the BIOS and clear the NVRAM and any previous errors
  • Remove all devices
  • If LEDs change, add parts back one at a time until the fault recurs and contact your technical support
  • If the fault remains the same with parts removed, contact your technical support
1 2 and 4 on 12 4   Reserved
  • Reserved
1 2 and 3 on 123 POV POST completes — Onscreen error message.
  • Troubleshoot as per the error message on-screen
1 2 3 and 4 on 1234 STD POST completes — operating system hand-off complete.
  • The Power On Self-Test has passed all checks
  • Troubleshoot the hard drive and the Operating System

Beep Codes

Beep Code Description Suggested Resolution
1-1-2 CPU register test in progress Contact Technical Support.
1-1-3 CMOS read/write test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
1-1-4 BIOS ROM checksum in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
1-2-1 Timer Test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
1-2-2 DMA initialization in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
1-2-3 DMA page register read/write test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
1-3-1 RAM refresh verification in progress or failure. Troubleshoot the memory and memory slots.
1-3-2 First 64 K RAM test in progress or failure Troubleshoot the memory and memory slots.
1-3-3 First 64 K RAM chip or data line failure (multi bit) Troubleshoot the memory and memory slots.
1-3-4 First 64 K RAM odd or even logic failure Troubleshoot the memory and memory slots.
1-4-1 First 64 K RAM address line failure Troubleshoot the memory and memory slots.
1-4-2 First 64 K RAM parity test in progress or failure Troubleshoot the memory and memory slots.
1-4-3 Fail-safe timer test in progress Troubleshoot the memory and memory slots.
1-4-4 Software NMI port test in progress Troubleshoot the memory and memory slots.
2-1-1 First 64 K RAM chip or data line failure - bit 0 Troubleshoot the memory and memory slots.
2-1-2 First 64 K RAM chip or data line failure - bit 1 Troubleshoot the memory and memory slots.
2-1-3 First 64 K RAM chip or data line failure - bit 2 Troubleshoot the memory and memory slots.
2-1-4 First 64 K RAM chip or data line failure - bit 3 Troubleshoot the memory and memory slots.
2-2-1 First 64 K RAM chip or data line failure - bit 4 Troubleshoot the memory and memory slots.
2-2-2 First 64 K RAM chip or data line failure - bit 5 Troubleshoot the memory and memory slots.
2-2-3 First 64 K RAM chip or data line failure - bit 6 Troubleshoot the memory and memory slots.
2-2-4 First 64 K RAM chip or data line failure - bit 7 Troubleshoot the memory and memory slots.
2-3-1 First 64 K RAM chip or data line failure - bit 8 Troubleshoot the memory and memory slots.
2-3-2 First 64 K RAM chip or data line failure - bit 9 Troubleshoot the memory and memory slots.
2-3-3 First 64 K RAM chip or data line failure - bit A Troubleshoot the memory and memory slots.
2-3-4 First 64 K RAM chip or data line failure - bit B Troubleshoot the memory and memory slots.
2-4-1 First 64 K RAM chip or data line failure - bit C Troubleshoot the memory and memory slots.
2-4-2 First 64 K RAM chip or data line failure - bit D Troubleshoot the memory and memory slots.
2-4-3 First 64 K RAM chip or data line failure - bit E Troubleshoot the memory and memory slots.
2-4-4 First 64 K RAM chip or data line failure - bit F Troubleshoot the memory and memory slots.
3-1-1 Secondary DMA register test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-1-2 Primary DMA register test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-1-3 Primary IMR test in progress or failure Contact Technical Support.
3-1-4 Secondary IMR test in progress or failure Contact Technical Support.
3-2-2 Interrupt vector loading in progress Contact Technical Support.
3-2-4 Keyboard controller test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-3-1 CMOS power fail and checksum test in progress Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-3-2 CMOS Config info validation in progress Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-3-3 RTC/Keyboard controller not found Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-3-4 Screen memory test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-4-1 Screen initialization test in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-4-2 Screen retrace tests in progress or failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
3-4-3 Search for video ROM in progress Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
4-2-1 The interrupt test for the timer tick is either in progress or failed. Contact Technical Support.
4-2-2 The shut-down test is in progress or has failed. Contact Technical Support.
4-2-3 Gate A20 failure Contact Technical Support.
4-2-4 Unexpected interrupt in Protected Mode. Contact Technical Support.
4-3-1 RAM test in progress or failure above address 0FFFFh Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
4-3-2 No memory in Bank 0 Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
4-3-3 Interval Timer Channel 2 test in progress or failure Contact Technical Support.
4-3-4 Time-Of-Day Clock test in progress or failure Contact Technical Support.
4-4-1 Super I/O chip failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)
4-4-4 Cache test failure Run the Dell Diagnostics. For more information, reference:  Resolve Hardware Issues With Integrated and Online Diagnostics (SupportAssist ePSA, ePSA, or PSA Error Codes)

See the table for definitions of the acronyms within this article.

Definition Acronym
Basic Input/Output System BIOS
Resource Configuration CFG
Central Processing Unit CPU
Dual In-line memory module DIMM
Direct Memory Access DMA
Embedded Controller EC
Host Embedded Controller Interface HECI
Liquid Crystal Display LCD
Light Emitting Diode LED
Motherboard Failure MBF
Memory-integrated Self-Test MBIST
Management Engine ME
Memory MEM
Non-Volatile Random Access Memory NVRAM
Peripheral Component Interconnect PCI
Post-video Activity POV
Pre-video Activity PRV
Power Supply Unit PSU
Random Access Memory RAM
Recovery Mode RCM
Read-Only Memory ROM
Real-Time Clock RTC
The Computers Power State is S0 - This is the Working State, where your Windows device is awake. S0
The Computers Power State is S1 - In this sleep state, the CPU is stopped, and your device is in standby mode. S1
The Computers Power State is S2 - This state is similar to S1 except that the CPU and device cache are lost because the processor loses power. S2
The Computers Power State is S3 - In this state, data is saved to RAM, hard drives, and other hardware are shut down. S3
The Computers Power State is S4 - In this state, RAM, and other data are saved to the hard disk. S4
The Computers Power State is S5 - The device is off.  S5
Small Board Interface Operating System SBIOS
Serial Peripheral Interface SPI
Boot Hand Off STD
Storage Device STO
Trusted Platform Module TPM
Universal Serial Bus USB
Video VID

If you require further assistance, contact Dell Technical Support.

Additional Information

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Article Properties
Article Number: 000153002
Article Type: How To
Last Modified: 15 Nov 2024
Version:  11
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