Rear M.2 LEDs
This topic provides troubleshooting information for the rear M.2 drive assembly.
LEDs on the rear M.2 interposer

| LED | Status and description | 
|---|---|
| 1 Activity LED (green) | On: The M.2 drive is idle. | 
| Off: The M.2 drive appears de-asserted. | |
| Blinking (about four flashes per second): The I/O activity of the M.2 drive is in progress. | |
| 2 Status LED (yellow) | On: A drive fault occurs. | 
| Off: The M.2 drive is working normally. | |
| Fast blinking (about four flashes per second): The M.2 drive is being located. | |
| Slow blinking (about one flash per second): The M.2 drive is being rebuilt. | 
Rear M.2 drive de-asserted problem
- Hot-swap the two side-by-side M.2 drive assemblies with each other to see if the problem persists. 
- If the problem persists: - Scenario 1: activity LED remains off, replace the interposer. If replacing interposers does not work, it can be a power or PSoC fault, collect FFDC file and contact Lenovo Support. 
- Scenario 2: both LEDs are on, access the drive information on XCC:- If the information is accessible but the drive remains de-asserted, replace the drive or check RAID chip log in FFDC file to see if any helpful information is available. 
- If the information is not accessible, check RAID chip log in FFDC file, replace the interposer or drive. 
 
 
- If the problem persists after replacing the interposer and drive, contact Lenovo Support. 
LEDs on the rear M.2 backplane

| LED | Status and description | 
|---|---|
| 1 System heartbeat LED (green) | Blinking: Power on and the RAID firmware is working normally. | 
| Off: Power off or the RAID firmware is working abnormally. | |
| 2 PSoC heartbeat LED (green) | On: The PSoC firmware is working abnormally. | 
| Off: Power off or the PSoC firmware is working abnormally. | |
| Fast blinking (about one flash per second): Updating code (bootloader mode). | |
| Slow blinking (about one flash every two seconds): Exiting initialization (application mode). The PSoC firmware is working normally. | 
Rear M.2 drive backplane troubleshooting procedure
- Visually inspect the LEDs on the backplane, with system power on and top cover removed. - If the PSoC heartbeat LED is always on or off, replace the backplane. If the problem persists after replacing, collect FFDC file and contact Lenovo Support. 
- If the system heartbeat LED is not blinking, it indicates that RAID chip problems occur. Replace the backplane. If the problem persists after replacing, collect FFDC file and contact Lenovo Support. 
 
- If XCC event log shows PCIe errors concerning the rear M.2 drive and removing the top cover is not feasible. - Replace the backplane. If the problem persists after replacing, collect FFDC file and contact Lenovo Support. 
- Check PSoC register in the PSoC folder to further identify if PSoC is working normally: - If not, try to replace the backplane or update PSoC firmware. If they do not work, contact Lenovo Support. 
- If yes, check if RAID chip information is accessible on FFDC file device list. If yes, replace the backplane or collect FFDC file and contact Lenovo Support; if not, replace the backplane.