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
Engine Control Module (ECM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device
Inflatable Restraint Sensing and Diagnostic Module (SDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device
Instrument Panel Cluster (IPC) |

• | High Speed GMLAN

• | Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Passenger Presence System Sensor | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device
Radio | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device
Theft Deterrent Module (TDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device
Transmission Control Module (TCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device
Vehicle Communication Interface Module (VCIM) |

• | High Speed GMLAN - pass through only

• | Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device