Class 2 Serial Data
The Class 2 serial data link allows modules to transmit, receive,
or exchange data:
|     •  | electronic climate control module (ECCM) | 
 
|     •  | transfer case shift control module (TCSCM) | 
 
|     •  | electronic brake control module (EBCM) | 
 
|     •  | powertrain control module (PCM) | 
 
|     •  | vehicle interface unit (VIU) | 
 
|     •  | body control module (BCM) | 
 
|     •  | instrument panel cluster (IPC) | 
 
|     •  | driver information center (DIC) | 
 
|     •  | 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.