Data Link Communications Circuit Description and Operation
The Class 2 serial data link allows modules to transmit, receive,
or exchange data between each other:
| • | HVAC control module (HCM) |
| • | Rear wheel steering module (RWS) |
| • | Suspension control module (SCM) |
| • | Active transfer case (ATC) |
| • | Electronic brake control module (EBCM) |
| • | Powertrain control module (PCM) |
| • | Transmission control module (TCM) |
| • | Body control module (BCM) |
| • | Instrument panel cluster (IPC) |
| • | Driver information center (DIC) |
| • | Mirror memory module (MMM) |
| • | Memory seat module (MSM) |
| • | Inflatable restraint sensing and diagnostic module (SDM) |
Circuit Description
Modules connected to the class 2 serial data circuit monitor
for serial data communications during normal vehicle operation. Operating
information and commands are exchanged among the modules. In addition to
this, Node Alive messages are transmitted by each module on the class 2
serial data circuit about once every 2 seconds. When the module
detects the class 2 serial data circuit shorted, the setting of all
other class 2 serial communication DTCs is inhibited and a U1300,
U1301, or a U1305 DTC will set.
