Troubleshooting Guide
A–4 www.hp.com Troubleshooting Guide
POST Error Messages
Warning: CPU fan 
has failed. 
CPU Fan weak (RPM < 
1000) or not turning. 
Ensure that the CPU fan power cable is 
connected. If the problem persists, contact 
an authorized service center for 
assistance.
Warning: System 
Fan has failed.
System Fan weak (RPM < 
1000) or not turning.
Ensure that the System fan power cable is 
connected. If the problem persists, contact 
an authorized service center for 
assistance.
Memory is running 
at Single Channel 
Mode
When two same size 
memories are put in slot 
1 and 3, this message 
will be displayed. 
For optimal performance, shut down the 
system and move the second DIMM from 
the XMM3 to the XMM2 socket.
Numeric Codes and Text Messages (Continued)
Code/Message Probable Cause Recommended Action










