Data Link References

This table identifies which serial data link that a particular module uses for in-vehicle data transmission. Some modules may use more than one data link to communicate. This table is used to assist in correcting a communication malfunction between the control module and the scan tool. For the description and operation of these serial data communication circuits refer to Data Link Communications Description and Operation .

Control Module	Data Link Type	Diagnostic Procedure
Schematic Reference: Data Communication Schematics
Audible Alert Control Module (CHIME) (w/UL5)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Auxiliary Heater Control Module (FOH) (w/K08, Coolant Heater)	High Speed GMLAN	Scan Tool Does Not Communicate with High Speed GMLAN Device
Body Control Module (BCM)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Electronic Brake Control Module (EBCM)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Engine Control Module (ECM) (Diesel)	High Speed GMLAN Class 2	Scan Tool Does Not Communicate with Class 2 Device Scan Tool Does Not Communicate with High Speed GMLAN Device
Glow Plug Control Module (GPCM) (Diesel)	High Speed GMLAN	Scan Tool Does Not Communicate with High Speed GMLAN Device
Inflatable Restraint Sensing and Diagnostic Module (SDM)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Instrument Panel Cluster (IPC)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Powertrain Control Module (PCM) (Gas)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Radio (w/o UL5)	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Remote Control Door Lock Receiver (RCDLR) w/AUO	Class 2	Scan Tool Does Not Communicate with Class 2 Device
Transmission Control Module (TCM) (Diesel)	High Speed GMLAN	Scan Tool Does Not Communicate with High Speed GMLAN Device