GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Power and Signal Distribution 🢒 Data Communications 🢒 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

Chime

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Data Recorded Module (DRM)
    • Class 2
    • J1939

Electronic Brake Control Module (EBCM) (JE3)
    • Class 2
    • J1939

Electric Shift Selector

J1939

Scan Tool Does Not Communicate with J1939 Device

Engine Control Module (ECM) (LG4, LLY)
    • High Speed GMLAN
    • Class 2
    • J1939

Glow Plug Control Module (GPCM) (LG4, LLY)
    • High Speed GMLAN
    • J1939

Inflatable Restraint Sensing and Diagnostic Module (SDM) (AJ3, AK5)

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) (L18)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Radio (U1C, UM6, UM7)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Serial Data Gateway (SDG) Module (LG4, LLY)
    • Class 2
    • J1939

Transfer Case Shift Control Module (NP8)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Transmission Control Module (TCM) (MX4, MTW)
    • High Speed GMLAN
    • Class 2
    • J1939

Vehicle Communications Interface Module (VCIM) (UE1)

Class 2

Scan Tool Does Not Communicate with Class 2 Device