Regal L4-2.0L Turbo (2011)
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Serial data circuits shorted together between a control module and a terminating resistor
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A shorted terminating resistor
Testing the Serial Data Circuits for an Open/High Resistance
1. Ignition OFF, disconnect the harness connectors with the mid speed GMLAN serial data circuits at an easily accessible control module that is not
communicating.
2. Ignition OFF for 60 seconds, test for greater than 100k ohm between each pair of serial data circuits at the control module connector that was just
disconnected. Verify that one pair of serial data circuits are greater than 100k ohm.
‹› If each pair of serial data circuits is less than the specified range, replace the control module that was disconnected.
3. Connect the harness connectors at the control module that was disconnected.
4. Disconnect the harness connectors with the mid speed GMLAN serial data circuits at another control module, in the direction of the open circuit.
5. Ignition OFF for 60 seconds, test for greater than 100k ohm between each pair of serial data circuits at the control module connector that was just
disconnected. Verify that one pair of serial data circuits is greater than 100k ohm.
‹› If each pair of serial data circuits is less than the specified range, replace the control module that was just disconnected.
6. Repeat step 3 until one of the following conditions are isolated:
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An open/high resistance on the serial data circuit between 2 control modules or splice packs, if equipped
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An open/high resistance on the serial data circuit between a control module and a terminating resistor
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An open/high resistance terminating resistor
Repair Instructions
Perform the Diagnostic Repair Verification (See: Testing and Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Verification Tests
and Procedures) after completing the repair.
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GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Wiring Repairs/GMLAN Wiring Repairs)
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Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, setup, and programming
