Diagnostic codes and errors
This section presents information about diagnostic LED codes, LED color definitions, and POST error
messages to help you troubleshoot problems.
Diagnostic LED and audible (beep) codes
This section describes the front panel LED error and operation codes as well as the audible codes
that might occur before or during the POST.
Activity Possible cause Recommended action
Blue Power LED
*
on. No
beeps.
Computer on.
N/A
Blue Power LED
*
blinks
every two seconds.
*
No
beeps.
Computer in Sleep
mode (S3-Suspend to
RAM). Select models
only.
Blue Power LED
*
is off.
*
No beeps.
Computer in Hibernate
mode (S4-Suspend to
disk) or system is off
(S5).
Blue Power LED
*
blinks
three times*, once per
second.
*
No beeps.
Computer in Sleep
mode (S3-Suspend to
RAM). Select models
only.
Blue Power LED
*
blinks
four times*, once per
second.
*
No beeps.
Computer in Hibernate
mode (S4-Suspend to
disk).
User-selectable for details.
For the following LED activity and beeps, the beeps are heard through the chassis speaker. Blinks and beeps repeat for
five cycles, after which, only the blinks continue to repeat.
Red Power LED blinks
two times, once every
second, followed by a
two-second pause. Two
beeps.
CPU thermal protection
activated by either of
the following methods:
●
A fan might be
blocked or not
turning.
●
The heatsink and
fan assembly is not
properly attached
to the CPU.
CAUTION: Internal components might be powered even when
the computer is off. To prevent damage, disconnect the
computer power cord before you remove a component.
1. Make sure that the computer air vents are not blocked and
the cooling fan is running.
2. Open the access panel, press power button, and verify that
the CPU fan is spinning. If the CPU fan is not spinning,
make sure the fan cable is plugged into the computer board
header. Make sure the fan is fully and properly seated or
installed.
3. If fan is plugged in and seated properly, but is not spinning,
the problem might be in the CPU fan. Contact HP for
assistance.
4. Verify that the fan assembly is properly attached. If
problems persist, there might be a problem with the CPU
heatsink. Contact HP for assistance.
Red Power LED blinks
three times, once every
second, followed by a
two-second pause. Three
beeps.
CPU not installed (not
an indicator of bad
CPU).
1. Verify that the CPU is present.
2. Reseat the CPU.
92 Chapter 4 Diagnostics and troubleshooting