GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2009 🢒 Escalade 🢒 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. 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

Accessory Power Module (APM), w/ HP2

Powertrain expansion bus

DTC U0074

Air Conditioning Control Module (ACCM), w/ HP2

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Audio Amplifier

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Assist Step Control Module (ARB)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Battery Energy Control Module (BECM) w/ HP2

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Body Control Module (BCM)
    • High Speed GMLAN
    • Low Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Chime Module w/ UL5

Low Speed GMLAN

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

Power Inverter Module (PIM) w/ HP2
    • High Speed Hybrid GMLAN
    • High Speed GMLAN
    •  DTC U0074

Driver Door Switch (DDS)
    • Low Speed GMLAN
    • Local Interconnect Network (LIN)

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Driver Position (Memory Seat) Module

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

Electronic Suspension Control (ESC) Module

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Engine / Powertrain Control Module (ECM/PCM)
    • High Speed GMLAN
    • High Speed Hybrid GMLAN w/HP2
    •  DTC U0074 w/HP2

Fuel System Control Module (FSCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Glow Plug Control Module

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

Inertia Sensor w/ HP2

High Speed Hybrid GMLAN

DTC U0074

Inside Rearview Mirror (ISRVM)

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

Liftgate Module (LGM)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Passenger Door Switch (PDS)
    • Low Speed GMLAN
    • Local Interconnect
    • Network (LIN)

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Passenger Presence System (PPS) Module

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Power Steering Control Module (PSCM) w/ HP2

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Power Take Off (PTO) Module

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Radio

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Rear Heated / Vented Seat Control Module (RHVSM)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Rear Seat Audio (RSA) Module

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Remote Control Door Lock Receiver (RCDLR)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Roll Over Sensor (ROS)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Serial Data Gateway Module (SDGM) w/ HP2
    • High Speed Hybrid GMLAN
    • High Speed GMLAN
    • Low Speed GMLAN
    •  DTC U0074

Theft Deterrent Module (TDM)

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Trailer Brake Control Module (TBCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Transfer Case Control Module (TCCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Transmission Control Module (TCM)

High Speed GMLAN

Scan Tool Does Not Communicate with High Speed GMLAN Device

Ultrasonic Park Assist (UPA) Module

Low Speed GMLAN

Scan Tool Does Not Communicate with Low Speed GMLAN Device

Vehicle Communication Interface Module (OnStar® VCIM)
    • High Speed GMLAN - pass through only
    • Low Speed GMLAN