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 Link Connector Schematics  | ||||||
Audio Amplifier (AMP), w/UQ7 and Y91  | Class 2  | |||||
Body Control Module (BCM)  | Class 2  | |||||
Communication Interface Module (OnStar®), w/UE1  | Class 2  | |||||
Digital Radio Receiver (DRR), w/U2K  | Class 2  | |||||
Driver Door Module (DDM)  | Class 2  | |||||
Electro-Hydraulic Power Steering (EHPS) Module, w/HP2  | High Speed GMLAN  | |||||
Electronic Brake Control Module (EBCM)  | Class 2  | |||||
Energy Storage Control Module (ESCM), w/HP2  | High Speed GMLAN  | |||||
Engine Control Module (ECM), w/LLY  | 
 
  | |||||
Generator Battery Control Module (GBCM)  | Class 2  | |||||
Glow Plug Control Module (GPCM) w/LLY  | High Speed GMLAN  | |||||
HVAC Control Module  | Class 2  | |||||
Hybrid Control Module (HCM), w/HP2  | 
 
  | |||||
Inflatable Restraint Sensing and Diagnostic Module (SDM)  | Class 2  | |||||
Instrument Panel Cluster (IPC)  | Class 2  | |||||
Memory Seat Module (MSM), w/AN3  | Class 2  | |||||
Passenger Door Module (PDM)  | Class 2  | |||||
Powertrain Control Module (PCM)  | 
 
  | Scan Tool Does Not Communicate with High Speed GMLAN Device or  | ||||
Radio  | Class 2  | |||||
Rear Seat Audio (RSA) Controller, w/UK6  | Class 2  | |||||
Rear Seat Entertainment (RSE), w/U42  | Class 2  | |||||
Rear Wheel Steering Control Module (RWSCM), w/NYS  | Class 2  | |||||
Remote Playback Device - CD Player (CDX), w/U1S  | Class 2  | |||||
Starter/Generator Control Module (SGCM), w/HP2  | High Speed GMLAN  | |||||
Transfer Case Shift Control Module (TCSCM), w/NP1, NP8  | Class 2  | |||||
Transmission Control Module (TCM), w/M74  | 
 
  | Scan Tool Does Not Communicate with High Speed GMLAN Device or  | ||||