2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2029
* 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. Verify there are no other U code DTCs set.
瀚慖f other U code DTCs are set, diagnose them first. Refer to Control Module U Code List (See: Diagnostic Trouble Code
Descriptions/Control Module U Code List).
2. Refer to Data Link References (See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and
Inspection/Initial Inspection and Diagnostic Overview) to determine if the control module setting DTC U0074 is on the mid speed or chassis
high speed serial data circuits.
Circuit/System Testing
Note: Each control module may need to be disconnected to isolate a circuit fault. Use the schematic to identify the following:
* Control modules the vehicle is equipped with
* Mid speed or chassis high speed serial data circuit terminating resistors
* Control module locations on the serial data circuits
* Each control modules mid speed or chassis high speed serial data circuit terminals
1. Attempt to communicate with all control modules on the mid speed or chassis high speed serial data circuit. Refer to Data Link References (
See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and Inspection/Initial Inspection and Diagnostic
Overview). Communications should not be available with two or more control modules on the mid speed or chassis high speed serial data
circuit.
瀚慖f only one control module is not communicating, diagnose that control module only. Refer to DTC U0100-U02FF (See: U Code
Charts/U0100).
2. Disconnect the scan tool from the DLC. The following tests will be done at the DLC connector.
3. All access doors closed, ignition OFF for 60 seconds, test for less than 10 ohm between the ground circuit terminal 5 and ground.
瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, test for less than 3 V between the serial data circuits listed below and ground:
* Mid speed GMLAN serial data terminal 3
* Mid speed GMLAN serial data terminal 11
* Chassis high speed GMLAN serial data terminal 12
* Chassis high speed GMLAN serial data terminal 13
瀚慖f greater than the specified range, test the serial data circuit for a short to voltage. Refer to Testing the Serial Data Circuits for a Short to
Voltage.
5. Ignition OFF for 60 seconds, test for greater than 100 ohm between the serial data circuits listed below and ground:
* Mid speed GMLAN serial data terminal 3
* Mid speed GMLAN serial data terminal 11
* Chassis high speed GMLAN serial data terminal 12
* Chassis high speed GMLAN serial data terminal 13
瀚慖f not the specified value, test the serial data circuit for a short to ground. Refer to Testing the Serial Data Circuits for a Short to ground.
6. Test for 50-70 ohm between the serial data circuits listed below:
* Mid speed GMLAN serial data circuits terminal 3 and terminal 11
* Chassis high speed GMLAN serial data circuits terminal 12 and terminal 13
瀚慖f less than 35 ohm, test for a short between the serial data circuits. Refer to Testing the Serial Data Circuits for a Short between the
