GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 CTS 🢒 Accessories 🢒 Theft Deterrent 🢒 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. 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

Audio Amplifier

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Dash Integration Module (DIM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Digital Radio Receiver (DRR)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Driver Door Module (DDM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Driver Door Switch Assembly (DDSA)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Electronic Brake Control Module (EBCM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Engine Control Module (ECM)
    • Class 2
    • Keyword 2000 (LA3/LY9)
    • High Speed GMLAN (LY7)

Refer to Scan Tool Does Not Communicate with Keyword Data Line (LA3/LY9) or Scan Tool Does Not Communicate with High Speed GMLAN Device (LY7)

Front Passenger Door Module (FPDM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Instrument Panel Cluster (IPC)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Inflatable Restraint Sensing and Diagnostic Module (SDM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Headlamp - Left

Keyword 2000

Refer to Scan Tool Does Not Communicate with Keyword Data Line

Headlamp - Right

Keyword 2000

Refer to Scan Tool Does Not Communicate with Keyword Data Line

HVAC Control Module

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Left Rear Door Module (LRDM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Memory Seat Module (MSM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Radio

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Radio Antenna Module

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Rear Integration Module (RIM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Right Rear Door Module (RRDM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Transmission Control Module (TCM)
    • Keyword 2000 (LA3/LY9)
    • High Speed GMLAN (LY7)

Refer to Scan Tool Does Not Communicate with Keyword Data Line (LA3/LY9) or Scan Tool Does Not Communicate with High Speed GMLAN Device (LY7)

Theft Deterrent Control Module

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

TV Antenna Module

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device

Vehicle Communication Interface Module (VCIM)

Class 2

Refer to Scan Tool Does Not Communicate with Class 2 Device