2010 Cadillac Truck SRX FWD V6-3.0L Page 2182

2010 Cadillac Truck SRX FWD V6-3.0L Page 2182

瀚慖f the test lamp does not illuminate, test the circuit for an open/high resistance. If the circuits test normal, replace the BCM.

5. Ignition ON, verify that a test lamp illuminates between all B+ circuits and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test

the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the appropriate module.

6. Verify that a test lamp illuminates between all ignition voltage circuits and ground.

瀚慖f the test lamp does not illuminate, test the ignition voltage circuits for a short to ground or an open/high resistance. If the circuit fuse is

open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the appropriate module.

7. Test for less than 1 Ohms in the GMLAN serial data circuits between the non-communicating module and the module that displays the DTC.

瀚慖f greater than specified range, test the GMLAN serial data circuits for open/high resistance.

8. If all circuits test normal, replace the module that is not communicating.

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 module replacement, setup, and programming

U2199

DTC U2105-U2199

Diagnostic Instructions

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

Check - Vehicle) prior to using the 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.

Diagnostic Fault Information

Circuit/System Description

Modules connected to the high and low speed GMLAN 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.

The body control module (BCM) activates the high speed GMLAN serial data wake up and the accessory wake up serial data circuits by applying

voltage when the ignition key is in ACC, ON or START. The high speed GMLAN serial data wake up circuit wakes up the electronic brake control

module (EBCM) for bus communication and the accessory wake up serial data circuit wakes up the engine control module (ECM) and transmission

control module (TCM).

Conditions for Running the DTC

* The system voltage is between 9-16 volts.