Circuit Operation

There are two different serial data lines on this vehicle, UART (Universal Asynchronous Receiver/Transmitter) and Class 2. Because of the need for modules on the Serial Data Line to communicate with each other, the Body Control Module (PZM) acts as an interpreter for data communication between Class 2 and UART systems.

UART Data Line
On UART based communication systems, there is a "master" of the serial data line and remote transceivers. The master of this data line is the PZM. The master controls the message traffic on the serial data line by polling all of the modules on UART and then waits for the proper response. The control modules on the UART data line are:
^ ABS/Traction Control (EBTCM)
^ Body Control Module (PZM)
^ Continuously Variable Road Sensing Suspension (CVRSS)
^ Road Sensing Suspension (RSS)
^ Sensing and Diagnostic Module (SDM)

Class 2 Data Line
Class 2 data is transmitted at a higher speed and messages are configured differently than UART data. While UART uses a "master" to control serial data line traffic, Class 2 uses the "peer to peer" method along with message arbitration to manage data line traffic. The control modules on the Class 2 data line are:
^ Heater and A/C Programmer (ACM)
^ Body Control Module (PZM)
^ Cellular Telephone Module (PHN)
^ Climate Control Panel (CCP)
^ Instrument Panel Cluster (IPC)
^ Integrated Radio Controller (IRC)
^ Powertrain Control Module (PCM)
^ Memory Seat/Memory Mirror Module (MSM)
^ Remote Function Actuator (RFA)