GM Service Manual Online
For 1990-2009 cars only

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 Link Connector Schematics

Body Control Module (BCM)

    • High Speed GMLAN
    • Low Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device and Scan Tool Does Not Communicate with Low Speed GMLAN Device

Digital Radio Receiver (DRR)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Electronic Brake Control Module (EBCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

HVAC Control Module

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Instrument Panel Cluster (IPC)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Inflatable Restraint Sensing and Diagnostic Module (SDM)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Power Steering Control Module (PSCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Powertrain Control Module (PCM) Manual Transmission Only

    • High Speed GMLAN Communications Buss
    • Class 2 for diagnostics and SPS Programming Only

Scan Tool Does Not Communicate with High Speed GMLAN Device for communications malfunctions or Scan Tool Does Not Communicate with Class 2 Device for SPS malfunctions

Radio

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Remote Playback Device - CD Player (CDX)

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

Vehicle Communication Interface Module (VCIM)

    • High Speed GMLAN - pass through only
    • Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device