2010 Cadillac Truck Escalade RWD V8-6.2L Page 2774
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.
2 wake up signal circuits (5986, 5985) are energized by the body control module (BCM) to activate multiple modules including the drive motor
generator battery control module (BECM) when serial data is required. Wake up signal circuit (968) is energized by the serial data gateway module
(SDGM) to activate the BECM immediately after the BCM energizes circuit 5986 and 5985. The BECM compares the status of both wake up
circuits.
Conditions for Running the DTC
* The system voltage is between 9-18 volts.
* Ignition key OFF.
Conditions for Setting the DTC
The BECM receives voltage from the BCM on wake up signal circuit 5986 for 3 seconds with the ignition OFF.
Action Taken When the DTC Sets
The hybrid powertrain control module (HPCM) will set DTC U209D.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present, including a key ON condition when both wake up signals are energized.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* DTC U209D will only set as current with the ignition in the OFF position. It will become history when the ignition is turned ON.
* 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)).
* Different DTCs may set in different modules along with this DTC depending on where the fault occurs and the vehicle operating conditions
when the fault occurs.
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
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal
Protection Equipment (PPE) and proper procedures must be followed.
The High Voltage Disabling procedure will perform the following tasks:
