For 1990-2009 cars

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. Some modules may have multiple communication circuits passing through them without actively communicating on that data link. This table is used to assist in correcting a communication malfunction. 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
Body Control Module (BCM) |

• | High Speed GMLAN

• | Class 2

Scan Tool Does Not Communicate with Class 2 Device

Digital Radio Receiver (DRR), w/U2K | Class 2 | Scan Tool Does Not Communicate with Class 2 Device
Electronic Brake Control Module (EBCM), w/JM4 | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device
Instrument Panel Cluster (IPC) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device
Inflatable Restraint Sensing and Diagnostic Module (SDM) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device
Powertrain Control Module (PCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device
Power Steering Control Module (PSCM) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device
Radio | Class 2 | Scan Tool Does Not Communicate with Class 2 Device
Transmission Control Module (TCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device
Vehicle Communication Interface Module (VCIM), w/UE1 |

• | High Speed GMLAN - pass through only

• | Class 2

Scan Tool Does Not Communicate with Class 2 Device