The miscroprocessor-controlled modules in the vehicle communicate
with each other through the serial data lines. This vehicle uses 2 serial
data lines:
| • | The E&C serial data line |
| • | The class 2 serial data line |
E&C Serial Data Line
The E&C serial data line is UART-base communication system. UART
serial data lines have a master of the serial data line and remote transceivers.
The master controls the message traffic on the serial data line by polling
all of the remotes (control modules). The master then waits for the proper
response. The control modules on the E&C serial data line can include
the following modules:
| • | The compact disc (CD) player |
The E & C serial data line is not connected to the data link connector
(DLC) so it is not accessible with a scan tool.
Class 2 Data Line
The class 2 data is transmitted at a higher speed. The messages have
a different configuration than the UART data. While the UART uses a master
in order to control serial data line traffic, the class 2 uses the peer-to-peer
method, along with message arbitration, in order to manage the data line
traffic.
The control modules on the class 2 data line can include the following
modules:
| • | The body control module (PZM) |
| • | The cellular telephone module |
| • | The climate control panel (CCP) |
| • | The continuously variable road sensing suspension (CVRSS) module |
| • | The electronic brake and traction control module (EBTCM) |
| • | The heater and A/C programmer |
| • | The inflatable restraint sensing and diagnostic module (SDM) |
| • | The memory mirror module (MMM) |
| • | The powertrain control module (PCM) |
| • | The radio interface module (RIM) |
| • | The remote function actuator (RFA) module |
