Latitude 5401 Service Manual

How to run M-BIST

1. Press and hold both the M key on the keyboard and the power button to initiate M-BIST.
2. With both the M key and the power button held down, the battery indicator LED may exhibit two states:
   1. OFF: No fault detected with the system board
   2. AMBER: Indicates a problem with the system board
3. If there is a failure with the system board, the battery status LED will flash one of the following error codes for 30 seconds:

   Table 1. LED error codesLED error codes

   Blinking Pattern		Possible Problem
   Amber	White
   2	1	CPU Failure
   2	8	LCD Power Rail Failure
   1	1	TPM Detection Failure
   2	4	Unrecoverable SPI Failure

4. If there is no failure with the system board, the LCD will cycle through the solid color screens described in the LCD-BIST section for 30 seconds and then power off.