Cobalt L4-2.2L (2008)
15. Ignition OFF, disconnect the harness connector at the EBCM.
16. Attempt to communicate with the VCIM. Communication should not be available.
^
If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground
between the EBCM and the TCM. If the circuits test normal, replace the EBCM.
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21
*
23
17. Ignition OFF, disconnect the X2 harness connector at the VCIM.
18. Attempt to communicate with the EPS. Communication should not be available.
^
If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground
between the VCIM and the TCM. If the circuits test normal, replace the VCIM.
*
9
*
8
19. Ignition OFF, disconnect the X2 harness connector at the BCM. Attempt to communicate with the EPS. Communication should not be available.
^
If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground
between the BCM and the VCIM. If the circuits test normal, replace the BCM.
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2
*
20
20. Ignition OFF, disconnect the X2 harness connector at the EPS.
21. Ignition ON, test for less than 1 volt between the following serial data circuits of BCM and ground.
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4
*
5
^
If greater than the specified range, test the circuit for a short to voltage.
22. Test for infinite resistance between the following serial data circuits of BCM and ground.
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4
*
5
^
If less than the specified value, test the circuit for a short to ground.
23. Test for infinite resistance between the serial data circuits terminal 4 terminal 5 of the BCM.
^
If less than the specified Value, test the serial data circuits for a short between them.
24. If the circuits test normal, replace the EPS.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair. See: Testing and Inspection/Diagnostic Trouble Code Tests and Associated
Procedures/Verification Tests and Procedures
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GMLAN Wiring Repairs
Scan Tool Does Not Communicate with Low Speed GMLAN Device
Scan Tool Does Not Communicate with Low Speed GMLAN Device
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Testing and Inspection/Initial Inspection and
Diagnostic Overview/Diagnostic System Check - Vehicle
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Review Strategy Based Diagnosis for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions provides an overview of each diagnostic category.
