Diagnostic Fault Information
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.
The wake up signal circuit is energized by the serial data gateway (SDG) module to activate the drive motor generator power inverter module (PIM)
and the drive motor generator battery control module. If the wake up signal is not responded to by all three modules, this DTC sets in the SDG
module.
Conditions for Running the DTC
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A short circuit exists on the wake up signal circuit of the SDG module.
Action Taken When the DTC Sets
The malfunction indicator lamp (MIL) illuminates and the driver information center (DIC) displays the message Service Hybrid System.
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.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Hybrid Controls Schematics ()
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)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
* EL-48569 Terminal Covers
* EL-48900 HEV Safety Kit
