2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 693

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 693

Conditions for Clearing the DTC

* The DTC clears when the fault is no longer detected.

* The current DTC will become history when the request for the output is removed.

* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Horn Schematics (See: Lighting and Horns/Horn/Diagrams/Electrical Diagrams)

Connector End View Reference

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

Description and Operation

Horns System Description and Operation (See: Lighting and Horns/Horn/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

Command the horn ON and OFF with the scan tool. The horn should turn ON and OFF when changing between the commanded states.

Circuit/System Testing

1. Ignition OFF, disconnect the X4 harness connector at the underhood fuse block.

2. Connect a test lamp between the control circuit terminal G1 and B+.

3. Press and release the horn switch. The test lamp should turn ON and OFF when changing between the commanded states.

瀚慖f the test lamp is always ON, test the control circuit for a short to ground or a sticking horn switch. If the circuit tests normal, replace the

BCM.

瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage, an open high resistance, or a horn switch which is not closing.

If the circuit tests normal, replace the BCM.

4. If all circuits test normal, replace the underhood fuse block.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Underhood Electrical Center or Junction Block Bracket Replacement (See: Maintenance/Fuses and Circuit Breakers/Fuse Block/Service and

Repair/Removal and Replacement/Underhood Electrical Center or Junction Block Bracket Replacement)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup and programming

B2850

DTC B2850, B2855, B2870, or B2875

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