LaCrosse V8-5.3L (2008)
Important:
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Verify there are no DTCs set as current. If any DTCs are set as current, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See:
Powertrain Management/Computers and Control Systems/Testing and Inspection/Diagnostic Trouble Code Descriptions) and perform the
appropriate diagnostics/repairs before proceeding with symptom based diagnostics.
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Inspect the cruise control switches for any sticking or binding conditions.
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Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation (See: Lighting and
Horns/Description and Operation/Exterior Lighting Systems Description and Operation).
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With the ignition ON, cruise control On/Off switch ON, rotate the steering wheel to both steering stops while activating each cruise
control switch separately. With a scan tool, observe all cruise control switch parameters in the ECM/PCM. Ensure that each cruise
control switch activates and that each of the displayed switch position parameters match the currently activated switch, and do not read
Invalid. This will aid in locating an intermittent fault within the inflatable restraint steering wheel module coil.
1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement (See:
Restraint Systems/Air Bag Systems/Air Bag/Service and Repair).
2. Disconnect the cruise control switch.
3. Ignition ON, measure for 10 volts or greater at the cruise control supply voltage circuit terminal 1.
‹› If less than the specified value, test the cruise control switch supply voltage circuit for an open/high resistance or a short to ground.
4. Ignition ON, verify that a test lamp illuminates between the cruise control supply voltage circuit terminal 1 and the cruise control switch signal
circuit terminal 3.
‹› If the test lamp does not illuminate, test the cruise control switch signal circuit for an open or high resistance.
5. Ignition OFF, disconnect the harness connector X1 at the ECM/PCM.
6. Ignition ON, verify that a test lamp does not illuminate between the cruise control supply voltage circuit terminal 1 and the cruise control switch
signal circuit terminal 3 of the cruise control switch harness.
‹› If the test lamp illuminates, test the cruise control switch signal circuit for a short to ground.
7. If the circuits test normal, test the cruise control switch. If the circuits and the component tests are normal, replace the ECM/PCM.
Component Testing
Important: The cruise control switch must be ON in order to properly measure the resistance of the set/cruise and the resume/accel switches.
1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement (See:
Restraint Systems/Air Bag Systems/Air Bag/Service and Repair).
2. Disconnect the cruise control switch.
3. Cruise control switch ON, measure the resistance between terminals 1 and 3 of the cruise control switch. Individually activate and hold each cruise
control function switch and compare the resistance reading to the values in the table for the appropriate switch.
4. For the cancel switch, measure the resistance between terminals 1 and 5 of the cruise control switch. The meter reading should indicate O.L. with
the switch released, and less than 1 ohm with the switch pressed.
‹› If any resistance measurements for any of the switches are not within the listed resistance values, replace the cruise control switch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Diagnostic Trouble
Code Tests and Associated Procedures/Verification Tests and Procedures) after completing the diagnostic procedure.
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Steering Wheel Control Switch Assembly Replacement (See: Accessories and Optional Equipment/Sensors and Switches - Accessories and
Optional Equipment/Steering Mounted Controls Assembly/Service and Repair)
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Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM or PCM replacement, setup, and programming
