Sunday, June 7, 2020

2010 Cadillac Truck Escalade RWD V8-6.2L Page 1459

2010 Cadillac Truck Escalade RWD V8-6.2L Page 1459

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Drive Motor Battery System Description ()

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)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code

(DTC) Type Definitions)

Special Tools

EL-48900 HEV Safety Kit

Circuit/System Verification

Verify that P0C76 is not set.

If DTC is set, refer to High Voltage Contactor/Relay Malfunction ().

P0C77

DTC P0C77 or P1A20

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* 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 P0C77

- Hybrid Battery System Precharge Time Too Short

DTC P1A20

- Hybrid Battery System Precharge Time Too Long

Circuit/System Description

The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The drive motor generator

battery control module will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is

communicated from the drive motor generator battery control module to the hybrid powertrain control module (HPCM) through serial data. The

hybrid powertrain control module is the host controller for diagnostic trouble code (DTC) information.

The drive motor generator battery contains 3 high voltage contactors that allow the high voltage direct current (DC) batteries to be connected to the

vehicle or safely contain the DC high voltage within the drive motor generator battery assembly. The three contactor/relays are a positive high

voltage contactor, negative high voltage contactor, and the current limit relay.

The power-up sequence for the high voltage DC system occurs in the following order:

1. The drive motor generator battery control module performs a precharge test, by closing both the negative contactor and current limit relay.

Because the current limit relay routes the high voltage current through a current limit resistor, the hybrid battery terminal voltage should

increase at a steady, predictable rate.

2. When the drive motor generator battery control module observes that hybrid battery terminal voltage and hybrid battery calculated voltage