2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2772
Circuit/System Description
Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation.
Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are
needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are
used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the
transmitter module.
Wake up signal circuits are energized by the body control module (BCM) to activate the serial data gateway module (SDGM) and other modules,
including the BECM, immediately when serial data is required. Additionally after receiving this signal the SDGM energizes another wake up signal
to activate the drive motor generator battery control module (BECM) among others.
Conditions for Running the DTC
* The system voltage is between 9-16 volts.
* The ignition key is OFF.
Conditions for Setting the DTC
* The communication enable signal circuit is open/high resistance.
* The wake up signal circuit is shorted to voltage.
Action Taken When the DTC Sets
The MIL may illuminate and the DIC may display multiple messages.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
When testing circuits to the SDGM access can be accomplished by removing the instrument panel center trim panel. Note that this procedure does
not allow removal of the SDGM, only access to the connector. Refer to Instrument Panel Center Trim Panel Replacement (Cadillac) (See: Body
and Frame/Interior Moulding / Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Cadillac)
)Instrument Panel Center Trim Panel Replacement (Except Cadillac) (See: Body and Frame/Interior Moulding / Trim/Dashboard / Instrument
Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Except Cadillac)).
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
