GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2007 🢒 CTS 🢒 Engine 🢒 Engine Electrical 🢒 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

Audio Amplifier (AMP)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Dash Integration Module (DIM)

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

Driver Door Module (DDM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Driver Door Switch Assembly (DDSA)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Electronic Brake Control Module (EBCM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Engine/Powertrain Control Module (ECM/PCM)
    • Class 2 (LS6, LY7, LP1)
    • High Speed GMLAN (LY7, LP1)

Front Passenger Door Module (FPDM)

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

Inflatable Restraint Sensing and Diagnostic Module (SDM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Headlamp - Left, w/TR7

Keyword 2000

Scan Tool Does Not Communicate with Keyword Data Line

Headlamp - Right, w/TR7

Keyword 2000

Scan Tool Does Not Communicate with Keyword Data Line

HVAC Control Module

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Left Rear Door Module (LRDM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Memory Seat Module (MSM), w/A45

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Radio

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Radio Antenna Module

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Rear Integration Module (RIM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Right Rear Door Module (RRDM)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Transmission Control Module (TCM), w/M82

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Theft Deterrent Control Module (VTD)

Class 2

Scan Tool Does Not Communicate with Class 2 Device

TV Antenna Module, wU2Y

Class 2

Scan Tool Does Not Communicate with Class 2 Device

Vehicle Communication Interface Module (VCIM), w/UE1

Class 2

Scan Tool Does Not Communicate with Class 2 Device