Data Link Communications

DATA LINK COMMUNICATIONS DESCRIPTION AND OPERATION

CLASS 2 SERIAL DATA LINK
The class 2 serial data link allows the following modules to communicate with each other:
- The body control module (BCM)
- The digital radio receiver (DRR)
- The electronic brake control module (EBCM)
- The inflatable restraint sensing and diagnostic module (SDM)
- The instrument panel cluster (IPC)
- The powertrain control module (PCM)
- The radio
- Vehicle communication interface module (VCIM)

The class 2 serial data link also allows a scan tool to communicate with the above modules for diagnostic and testing purposes.

DATA LINK CONNECTOR (DLC)
The data link connector (DLC) allows a scan tool to communicate with the class 2 modules. The DLC is a standardized 16 cavity connector located below the instrument panel and close to the steering column. Connector design and location is dictated by an industry wide standard, and it is required to provide the following:
- Scan tool power battery positive voltage at terminal 16
- Scan tool power ground at terminal 4
- Class 2 serial data signal at terminal 2
- Common signal ground at terminal 5

Refer to Computer/Integrating Systems Connector End Views.

DIAGNOSTIC TROUBLE CODES (DTCS)
Each control module connected to the class 2 serial data circuit monitors serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition, node alive messages are transmitted by each module on the class 2 serial data circuit about once every 2 seconds. If a module does not receive a node alive message when expected, a DTC will set. If a module detects that the class 2 serial data circuit is shorted, the setting of all other class 2 serial communication DTCs is inhibited, and DTC U1300, U1301, or U1305 will set.