How to Run the LCD Built-in Self-Test on a Dell Laptop

If the LCD screen on a Dell laptop is experiencing any of the following symptoms, running a diagnostic test can help identify if the display issue is inherent to the LCD screen.

• Flickering
• Blurry, fuzzy, or distorted image
• Horizontal or vertical lines
• Geometric distortion or skewed image
• Distorted or fading colors
• Bright or dead pixels
• Light leak
• Image burn, bright, or black patch
• Bubbles or air pockets

If the display issue is with a Dell monitor, see the Dell knowledge base article How to Run a Diagnostic Test on a Dell Monitor.

Display or video issues can be caused due to outdated graphics drivers, hardware failure (LCD screen), or incorrect video settings on the computer.

Running a diagnostic test on the LCD screen helps identify if the issue is an inherent hardware problem with the LCD screen.

Table of Contents:

1. LCD Built-in Self-Test (BIST)
2. Enhanced LCD Diagnostics

LCD Built-in Self-Test (BIST)

Dell laptops have a built-in diagnostic tool that helps determine if the screen abnormality is an inherent problem with the LCD screen of the Dell laptop, the video card (GPU), or the display settings on the computer. If you notice screen abnormalities like flickering, distortion, clarity issues, fuzzy or blurry images, horizontal or vertical lines, color fade, bubbles, it is a good practice to isolate the LCD screen by running a diagnostic test. The LCD built-in self-test can be initiated in two ways:

Method 1:

1. Turn off the computer.
2. Disconnect any devices that are connected to the computer.
3. Connect the AC adapter (charger) to the computer.
4. Ensure that the LCD screen is clean (no dust particles on the surface of the screen).
5. Press and hold the D key and turn on the computer to enter LCD built-in self-test (BIST) mode. Continue to hold the D key, until you see color bars on the LCD screen.
6. The screen displays multiple colors to black, white, red, green, and blue.
7. Carefully inspect the screen for abnormalities.
8. At the end of the last color (red), the computer restarts.
9. If the screen abnormality is not present in the built-in self-test mode, see the Dell knowledge base article How to Troubleshoot Display or Video Issues on a Dell Laptop.
10. If the screen abnormality is present in the built-in self-test mode, contact Dell Technical Support for repair options available at your location.

Method 2:

1. Turn off the computer.
2. Disconnect any devices that are connected to the computer.
3. Connect the AC adapter (charger) to the computer.
4. Ensure that the LCD screen is clean (no dust particles on the surface of the screen).
5. Press and hold the Fn key and turn on the computer to enter the preboot diagnostics mode. Continue to hold the Fn key, until you see the preboot diagnostic screen.
   NOTE: SupportAssist Pre-boot System Assessment or Enhanced Pre-Boot System Assessment (ePSA) diagnostic test checks the hardware and reports any hardware errors. Make a note of the error code or error message, validation code, and contact Dell Technical Support for repair options available in your location.
6. When you see the message "Do you see the color bars? Yes/No", press the N key to enter LCD built-in self-test mode.
   NOTE: If you do not respond for 30 seconds, the diagnostic test assumes your response as No and enters the LCD built-in self-test (BIST).
7. The screen displays multiple color bars and changes colors to black, white, red, green, and blue.
8. Carefully inspect the screen for abnormalities.
9. The computer restarts after the remaining tests are completed.
10. If the screen abnormality is not present in the built-in self-test mode, see Laptop Screen Not Working: Fix Common Display Issues.
11. If the screen abnormality is present in the built-in self-test mode, contact Dell Technical Support for repair options available at your location.

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Enhanced LCD Diagnostics

Dell is making improvements to the LCD Built-in Self-Test (BIST) laptop diagnostics for some computers.

• The LCD-Built-in Self-Test (BIST) has been updated to include a cracked glass diagnostic to help determine whether a laptop’s LCD is damaged. This feature can help detect a cracked LCD panel with higher certainty.
• The Enhanced LCD Diagnostics replace the legacy Two Amber, Seven White, and Two Amber, Eight White codes and expand them into four new LED flash codes that narrow down the exact failure and pinpoint specific failing parts:
  • Four Amber, Three White
  • Four Amber, Four White
  • Four Amber, Five White
  • Four Amber, Six White

Dell Technologies recommends updating to the BIOS version to the latest version. This would enable the new diagnostics if available for your computer. The new codes help to narrow down the problem further. If nothing can be seen on the laptop display, try to connect an external monitor to update the BIOS on the laptop. For more information about updating the BIOS, see Dell Technologies Knowledge Base article BIOS Update Guide.

Run the Enhanced LCD-BIST laptop diagnostics

The new Enhanced LCD-BIST is run in the same way as the existing LCD-BIST. The Enhanced LCD-BIST is now able to determine if the LCD panel is damaged or cracked. This feature gives an additional method of detecting cracks or damage to the LCD.

Dell Technologies recommends updating to the BIOS version to the latest version. This would enable the new diagnostics if available, for your computer. The new codes help to narrow down the problem further. If nothing can be seen on the laptop display, try to connect an external monitor to update the BIOS on the laptop. For more information about updating the BIOS, see Dell Technologies Knowledge Base article BIOS Update Guide.

To run the Enhanced LCD-BIST perform the following steps:

1. Turn off the laptop.
2. Disconnect any devices that are connected to the laptop.
3. Ensure that the AC adapter is connected to the laptop.
   Alternatively, use a powered Dell dock. (Without any other devices connected to the dock.)
4. Ensure that the LCD screen is clean and the can clearly view the display.
5. Press down the D key and power button simultaneously on the laptop. Continue to hold the D key until the screen displays any of the following solid colors:
   • Red
   • Green
   • Blue
   • Black
   • White
6. The screen displays solid colors and changes colors on the entire screen to white, black, red, green, and blue twice.
7. Carefully inspect the screen for abnormalities (any lines, fuzzy color, or distortion on the screen)
8. Look at the Battery or Power LED to see if it is flashing.
   
   NOTE: The positioning of the Battery or Power LED which displays the diagnostics flash codes changes depending on the model of laptop. (They are often located on either side of the laptop or around the keyboard.) Confirm the position by checking the User's Guide. For more information about obtaining the User's Guide, see Dell Knowledge Base article Dell Support Online Manuals Page
9. One of two scenarios may occur:
1. If no screen abnormality is present, or the Battery or Power LED is not flashing, see Laptop Screen Not Working: Fix Common Display Issues.
2. If the screen abnormality is present, or the Battery or Power LED is flashing, contact Dell Technical Support for repair options available at your location.

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Display Maintenance Guidelines

To learn more about best practices on handling and using a Dell laptop, see the Dell knowledge base article Best Practices for Product Use and Handling for Dell Laptops.

To learn more about general maintenance guidelines, see the Dell knowledge base article General Maintenance Guidelines For a Dell Computer.

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Safety Instructions

For displays with glossy bezels, consider the placement of the display as the bezel may cause disturbing reflections from surrounding light and bright surfaces.

To learn more about safety instructions, see the Dell knowledge base article Safety Precautions When Working with Electronic and Electrical Equipment.

For FCC notices (U.S. only) and other regulatory information, see the regulatory compliance website www.dell.com/regulatory_compliance.

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Frequently Asked Questions

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