LaCrosse FWD V6-3.0L (2010)
Malfunction Indicator Lamp: Testing and Inspection
Malfunction Indicator Lamp (MIL) Diagnosis
Diagnostic Instructions
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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.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Circuit/System Description
Ignition voltage is supplied to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control
circuit.
Reference Information
Schematic Reference
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Instrument Cluster Schematics (See: Diagrams/Electrical Diagrams/Instrument Cluster Schematics)
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Engine Controls Schematics (LLT) (See: Powertrain Management/Diagrams/Electrical Diagrams)Engine Controls Schematics (LF1) (See:
Powertrain Management/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
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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)
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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 Verification
Note: Any MIL requesting DTCs that may be set should be diagnosed first.
1. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
2. Ignition ON, observe each of the MIL Control Circuit Test parameters listed below with a scan tool:
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The MIL Control Circuit Low Voltage Test Status
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The MIL Control Circuit Open Test Status
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The MIL Control Circuit High Voltage Test Status
Each parameter should display OK or Not Run.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the K20 ECM.
2. Ignition ON, the MIL should not illuminate.
‹› If the MIL is illuminated, test the MIL control circuit terminal 46-X1 for a short to ground. If the circuit tests normal, replace the instrument
panel cluster (IPC).
Note: The MIL is powered by a dedicated ignition voltage circuit.
