U1813

DTC U1813

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC U1813 00

-
Battery Energy Control Module Bus B High Speed Communication Enable Circuit High

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 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 serial data gateway (SDG) module translates serial data messages between the high speed GMLAN serial data bus, the low speed GMLAN serial data bus, and the high speed hybrid GMLAN serial data bus. Messages between the drive motor generator battery control module and the other hybrid system control modules must pass thru the SDG module. The wake up circuit sends a voltage from the SDG module to the drive motor generator battery control module to initiate certain module functions. DTC U1813 is set by the drive motor generator battery control module, but is stored in and reported by the hybrid powertrain control module (HPCM).

Conditions for Running the DTC

* The system voltage is between 9-18 volts.

* Ignition is OFF.

Conditions for Setting the DTC

The drive motor generator battery control module receives voltage on wake up signal circuit for greater than 3 seconds when the ignition is OFF.

Action Taken When the DTC Sets

The hybrid system signals the engine control module (ECM) to request illumination of the malfunction indicator lamp (MIL).

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 U1813 will always set with SDG module DTC B137A 01.

Reference Information

Schematic Reference

* Data Communication Schematics Electrical Diagrams

* Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views Connector End Views By Name

Description and Operation

Data Link Communications Description and Operation Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Circuit/System Verification

Verify that DTC B137A is not set in the SDG module.

If the DTC is set, refer to DTC B137A B137A.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for module replacement, setup, and programming