2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2050
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 References
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Testing
Note: If more than one module is not communicating use Data Communication Schematics (See: Powertrain Management/Computers and
Control Systems/Information Bus/Diagrams/Electrical Diagrams) to determine which module is closest to the DLC. Start diagnostics with that
module.
Terminal and connector identifiers will be different depending on the individual module being tested. Use Schematic Reference and Connector End
View Reference to determine which connector and terminal to access.
1. Using the DTC Descriptor and Diagnostic Aids, determine the module that is not communicating that should be tested.
2. Ignition OFF, disconnect the harness connector of the module that is not communicating.
3. Test for less than 2 ohms between the module ground circuits and ground.
瀚慖f greater than specified range, test the ground circuit for an open/high resistance.
Note: Only the high speed GMLAN modules have a wired serial data wake up circuit. Refer to the module schematics to identify which
modules have a wake up circuit. If the module that is not communicating does not have a serial data wake up circuit, proceed to step 5.
4. Ignition ON, verify that a test lamp illuminates between the high speed GMLAN serial data wake up circuit OR the accessory wake up serial
data circuit and ground.
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
Verification Tests
Diagnostic Repair Verification
