"NO BUS" message means that the Programmable Communications Interface (PCI) data bus circuit is inoperative. This circuit is the data exchange between the PCM and other various computer modules and circuits in the vehicle.
The following could be reasons for a "No Bus" message:
*A instrument cluster CPU, RAM, or EEPROM failure (includes bad grounds or broken circuits on the instrument cluster PC board)
*A poor or broken PCI data bus connection at the instrument cluster
*Certain instrument cluster fuses may be open
Sunday, May 10th, 2009 AT 3:31 PM