2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3154

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3154

Repair Instructions

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

* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Wiring Repairs/GMLAN Wiring Repairs)

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

programming

U186A

DTC U186A

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 Descriptor

DTC U186A

- Lost Communication With Transfer Case Control Module

Circuit/System Description

Modules connected to the 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 also, 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.

Conditions for Running the DTCs

* The system voltage is between 9-16 volts.

* The vehicle power mode master indicates that the need for serial data communications.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTCs Sets

The modules is never signaled, therefore the specific subsystems will not function.