When Monitored And Set Condition:
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
When Monitored: With the ignition on and the module transmitting information on the PCI BUS.
Set Condition: The code will set if the onboard diagnostic cannot detect the module transmitting information on the PCI BUS for 4 consecutive seconds.
NOTE:
Any PCI Bus Failure will may cause a stored code to set.