Express 4500 V8-6.0L (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 Panel, Gauges and Warning Indicators/System
Diagram/Instrument Cluster Schematics)
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Engine Controls Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Connector
Repairs/Connector Repairs)
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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)
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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)
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 Status parameters listed below with a scan tool:
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The MIL Ckt Short Gnd Test Status
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The MIL Ckt Open Test Status
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The MIL Ckt Short Volts Test Status
Each parameter should display OK or Not Run
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 68-X1 for a short to ground. If the circuit tests normal, replace the P16
instrument panel cluster.
3. Connect a 3 A fused jumper wire between the MIL control circuit terminal 68-X1 and ground. The MIL should illuminate.
