2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3131

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3131

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

Circuit/System Verification

Verify that DTC U1814, U2099, B1428, B1370, B1380, B1440, or B1441 is not set.

If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic

Trouble Code (DTC) List - Vehicle).

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:

* Identify how to disable high voltage.

* Identify how to test for the presence of high voltage.

* Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must

be followed.

Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

* Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.

- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or

not.

Failure to follow the procedures exactly as written may result in serious injury or death.

Note: Use the schematic to identify the following:

* Control modules the vehicle is equipped with

* Control module locations on the low and high speed GMLAN serial data circuits

* The control modules B+, ignition, ground, communication enable and serial data circuit terminals

1. Determine the control module that is not communicating. Refer to Control Module U Code List (See: Diagnostic Trouble Code

Descriptions/Control Module U Code List).

2. Using the Hybrid High Voltage Module Chart below, verify that the non-communicating control module is not a high voltage module. If the

control module is a high voltage module, perform the High Voltage Disabling (See: Hybrid Drive Systems/Battery System, Hybrid

Drive/Testing and Inspection/Initial Inspection and Diagnostic Overview/High Voltage Disabling) procedure before proceeding with this

diagnostic.

3. If high voltage disabling is required, reconnect the 12 V battery after performing the high voltage disabling procedure.

4. Ignition OFF, disconnect the harness connector of the control module that is not communicating.

5. Test for less than 10 ohm between each ground circuit terminal and ground.

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.