The miscroprocessor-controlled modules in the vehicle communicate
with each other through serial data lines. This vehicle uses the following
3 serial data lines:
| • | The UART serial data line |
| • | The E&C serial data line |
| • | The class 2 serial data line |
UART Serial Data Line
UART-based communication systems 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 UART data line may include the following
modules:
| • | The electronic brake (and traction) control module (EBCM/EBTCM) |
| • | The inflatable restraint sensing and diagnostic module (SDM) |
| • | The heater and A/C programmer |
| • | The heater and A/C control |
| • | The powertrain control module (PCM) |
| • | The cellular telephone module |
E&C Serial Data Line
The E&C serial data line is a 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 may include
the following modules:
| • | The heater and A/C control |
| • | The heater and A/C programmer |
| • | The compact disc (CD) changer |
| • | The cellular telephone module |
Class 2 Data Line
Class 2 data is transmitted at a higher speed. The messages have
a different configuration than UART data. While UART uses a master in order
to control serial data line traffic, 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 may include the
following modules:
| • | The powertrain control module (PCM) |
| • | The remote function actuator (RFA) module |
