2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3281

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3281

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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 (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical

Diagrams)

* Hybrid Controls Schematics (See: Hybrid Drive Systems/Diagrams/Electrical Diagrams)

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)