2010 Cadillac CTS Sedan AWD V6-3.0L Page 2048
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/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/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. Ignition OFF, disconnect the X1 harness connector at the ECM and the TCM one at a time. After each disconnect, test for current DTCs.
DTC U1814 should remain current.
瀚慖f the DTC becomes history, replace the module disconnected when the DTC became history.
2. Ignition OFF, disconnect the X4 harness connector at the BCM.
3. Test for infinite resistance between the signal circuit terminal 19 and ground.
瀚慖f less than the specified value, test the signal circuit for a short to ground.
4. If all circuits tests normal, replace the BCM.
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 module replacement, setup, and programming
* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/GMLAN Wiring Repairs)
U1826
DTC U1826 or U1827
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 U1826 71
- Lost Communication With Multi-Axis Acceleration Sensor Module on Bus "B" Invalid Serial Data Received
DTC U1826 72
- Lost Communication With Multi-Axis Acceleration Sensor Module on Bus "B" Alive Counter Incorrect/Not Updated
DTC U1826 7F
- Lost Communication With Multi-Axis Acceleration Sensor Module on Bus "B" Erratic
DTC U1827 71
- Lost Communication With Steering Angle Sensor Module on Bus "B" Invalid Serial Data
DTC U1827 72
- Lost Communication With Steering Angle Sensor Module on Bus "B" Alive Counter Incorrect/Not Updated
DTC U1827 74
- Lost Communication With Steering Angle Sensor Module on Bus "B" Value of Signal Protection Calculation Incorrect
