Device Status Lights - Dell Latitude E5550 Owner's Manual

1. Shutdown the computer.
2. Press and hold the <fn> key, while pressing the power button, and then release both.
The Enhanced Pre-boot System Assessment window displays, listing all devices detected in the
computer. The diagnostics starts running the tests on all the detected devices.
3. On the boot menu screen, select the Diagnostics option.
The Enhanced Pre-boot System Assessment window displays, listing all devices detected in the
computer. The diagnostics starts running the tests on all the detected devices.
4. If you wish to run a diagnostic test on a specific device, press <Esc> and click Yes to stop the
diagnostic test.
5. Select the device from the left pane and click Run Tests
6. If there are any issues, error codes are displayed.
Note the error code and contact Dell.

Device Status Lights

Table 29. Device Status Lights
Turns on when you turn on the computer and blinks when the computer is in a power
management mode.
Turns on when the computer reads or writes data.
Turns on steadily or blinks to indicate battery charge status.
Turns on when wireless networking is enabled.
The device status LEDs are usually located either on the top or left side of the keyboard. They display the
storage, battery and wireless devices connectivity and activity. Apart from that they can be useful as a
diagnostic tool when there's a possible failure to the system.
The following table lists how to read the LED codes when possible errors occur.
Table 30. LED Lights
Storage LED Power LED
Blinking Solid
Solid Blinking
Blinking Blinking
Blinking Blinking
Blinking Blinking
Blinking Off
Solid Blinking
Wireless LED Fault Description
Solid A possible processor failure has occurred.
Solid The memory modules are detected but encountered
an error.
Blinking A system board failure has occurred.
Solid A possible graphics card/video failure has occurred.
Off System failed on hard drive initialization OR System
failed in Option ROM initialization.
Blinking The USB controller encountered a problem during
initialization.
Blinking No memory modules are installed/detected.
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