For 1990-2009 cars

The miscroprocessor-controlled modules in the vehicle communicate with each other through the serial data lines. This vehicle uses 3 serial data lines as follows:

• | 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 can 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 powertrain control module (PCM)

• | The instrument cluster

• | The transmission position decoder module

### 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 radio

• | The heater and A/C control

• | The heater and A/C programmer

### 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 can include the following modules:

• | The powertrain control module (PCM)

• | The remote function actuator (RFA) module