2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 788

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 788

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 Testing

1. Inspect the trailer rear fog lamp bulb for an open or shorted filament.

瀚慖f the bulb is inoperable, replace the bulb.

2. Park lamp switch OFF, clear the DTC, test the trailer rear fog lamp circuit for a short to voltage, short to ground, an open, or high resistance.

瀚慖f all circuits/connections test normal, replace the XBCM.

Repair Instructions

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

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

Gasoline With LY6, or Diesel

DTC B3894 (Gasoline With LY6, or Diesel)

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) provide an overview of each diagnostic category.

DTC Descriptor

DTC B3894 5A

- Stop Lamp Switch Circuit Plausibility Failure

Circuit/System Description

The brake switch is hard wired to the trailer brake control module (TBCM). The body control module (BCM) sends a brake switch status serial data

message to the trailer brake control module. The trailer brake control module compares the states of the brake switch signal to the serial data

message after a master cylinder brake pressure sensor threshold is exceeded. If the brake switch signal and the serial data message are not in

agreement or if the serial data message is not valid, a DTC will set and the trailer brake control system will be disabled.

Conditions for Running the DTC

* Battery voltage is 9.5-17 V.

* The module initialization has taken place.

* The master cylinder brake pressure exceeds threshold

Conditions for Setting the DTC

* The brake switch serial data message is not valid.

* The actual brake switch input to the trailer brake control module, and the serial data information for the brake switch do not match.

Action Taken When the DTC Sets

* The trailer brake control will be disabled for the remainder of the ignition cycle.

* The driver information center will display Service Trailer Brake System.