Service Manual

Table 20. LED codes
Diagnostic light codes
(Amber, white)
Problem description
1,1 TPM detection failure
1,2 Unrecoverable SPI flash failure
1,3 Short in hinge cable tripped OCP1
1,4 Short in hinge cable tripped OCP2
1,5 EC unable to program i-Fuse
1,6 EC internal failure
2,1 Processor failure
2,2 System board: BIOS or Read-Only Memory
(ROM) failure
2,3 No memory or Random-Access Memory (RAM)
detected
2,4 Memory or Random-Access Memory (RAM)
failure
2,5 Invalid memory installed
2,6 System-board or chipset error
2,7 Display failure - SBIOS message
2,8 Display failure - EC detection of power rail
failure
3,1 CMOS battery failure
3,2 PCI, video card/chip failure
3,3 BIOS recovery image not found
3,4 Recovery image found but invalid
3,5 Power-rail failure
3,6 System BIOS Flash incomplete
3,7 Management Engine (ME) error
Camera status light: Indicates whether the camera is in use.
● Solid white — Camera is in use.
● Off — Camera is not in use.
Caps Lock status light: Indicates whether Caps Lock is enabled or disabled.
● Solid white — Caps Lock enabled.
● Off — Caps Lock disabled.
Built-in self-test (BIST)
About this task
There are three different types of BIST to check the performance of display, power rail, and system board. These tests are
important to evaluate if an LCD or system board needs a replacement.
1. M-BIST: M-BIST is the system board built-in self-test diagnostics tool that improves the diagnostics accuracy of system
board embedded controller (EC) failures. M-BIST must be manually initiated before POST and can also run on a dead
system .
2. L-BIST: L-BIST is an enhancement to the single LED error code diagnostics and is automatically initiated during POST.
3. LCD-BIST: LCD BIST is an enhanced diagnostic test that is introduced through Preboot System Assessment (PSA) on legacy
systems.
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Troubleshooting