Malfunction Indicator Lamp (MIL) Diagnosis
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Malfunction Indicator Lamp (MIL) Diagnosis
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Circuit/System Description
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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.
If the condition is intermittent, move the related harnesses and connectors with the engine operating. Monitor the scan tool Circuit Test Status parameters for the component. The Circuit Test Status parameter will change from OK or Not run to Fault if there is a condition with the circuit or a connection.
Schematic Reference
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Verification
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Note
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Any MIL requesting DTCs that may be set should be diagnosed first.
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1.
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Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
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2.
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Ignition ON, observe each of the MIL Control Circuit Test parameters listed below with a scan tool:
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•
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The MIL Control Circuit Low Voltage Test Status
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•
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The MIL Control Circuit Open Test Status
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•
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The MIL Control Circuit High Voltage Test Status
Each parameter should display OK or Not Run.
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1.
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Ignition OFF, disconnect the X1 harness connector at the K20 ECM.
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2.
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Ignition ON, the MIL should not illuminate.
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3.
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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 P16 instrument panel cluster.
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4.
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Connect a 3 A fused jumper wire between the MIL and ground. The MIL should turn on.
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5.
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If the MIL does not illuminate, test the MIL control circuit for a short to voltage or an open/high resistance. If the MIL control circuit tests OK, test the instrument panel cluster ignition circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the instrument panel cluster\bulb.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Instrument Cluster Replacement
Control Module References
for replacement, setup, and programming