2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2033
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Description and Operation
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 Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Determine the control module that is not communicating. Refer to Control Module U Code List (See: Diagnostic Trouble Code
Descriptions/Control Module U Code List).
2. Verify that DTC U1814, U2099, B1428, B1370, B1380, B1440, or B1441 is not set.
瀚慖f any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
3. Engine running for 10 seconds.
4. Ignition ON, engine OFF, verify that DTC U0100-U0299 is not set with symptom byte 00.
瀚慖f the DTC U0100-U0299 is set with symptom byte 00, refer to Circuit/System Testing.
5. Verify that DTC U0100-U0299 is not set with symptom byte 71 or 72.
瀚慖f the DTC U0100-U0299 is set with symptom byte 71 or 72 along with other DTCs set, diagnose all other codes first. Refer to
Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List -
Vehicle).
瀚慖f the DTC U0100-U0299 is set with symptom byte 71 or 72 and without other DTCs set, reprogram the control module. If the DTC
resets, replace the control module.
Circuit/System Testing
Note: Use the schematic to identify the following:
* Control modules the vehicle is equipped with
* Control module locations on the low and high speed GMLAN serial data circuits
* The control modules B+, ignition, ground, communication enable and serial data circuit terminals
1. Ignition OFF, disconnect the harness connector at of the control module that is not communicating.
2. Test for less than 10 ohm between each ground circuit terminal and ground.
瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.
