Table 6. IMM error messages (continued)
v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 4, “Parts listing, System x3550 M3 Types 4254 and 7944,” on page 159 to determine which
components are customer replaceable units (CRU) and which components are field replaceable units
(FRU).
v If an action step is preceded by “(Trained service technician only),” that step must be performed only by a
trained service technician.
Sensor Pwr Rail B Fault has transitioned
to non-recoverable.
Error A sensor has changed to
Nonrecoverable state.
1. Turn off the server and
disconnect it from
power.
2. Remove the optical
drive, fans, hard disk
drives, and hard disk
drive backplane.
3. Reinstall each device,
one at a time, starting
the server each time to
isolate the failing
device.
4. Replace the failing
device.
5. (Trained service
technician only)
Replace the system
board.
Sensor Pwr Rail C Fault has
transitioned to non-recoverable.
Error A sensor has changed to
Nonrecoverable state.
1. Turn off the server and
disconnect it from
power.
2. (Trained service
technician only)
Remove the SAS/SATA
RAID riser card, the
DIMMs in connectors 1
through 8, and the
microprocessor in
socket 1.
3. Reinstall each device,
one at a time, starting
the server each time to
isolate the failing
device.
4. Replace the failing
device.
5. (Trained service
technician only)
Replace the system
board.
58 IBM System x3550 M3 Types 4254 and 7944: Problem Determination and Service Guide