C 1500 Truck 2WD V8-4.8L VIN V (2001)
Malfunction Indicator Lamp: Testing and Inspection
Malfunction Indicator Lamp (MIL) Always On
CIRCUIT DESCRIPTION
Battery positive voltage is supplied directly to the MIL. The Powertrain Control Module (PCM) turns the MIL ON by grounding the MIL control
circuit.
MIL OPERATION
The Malfunction Indicator Lamp (MIL) is located on the Instrument Panel (IP).
MIL FUNCTION
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The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
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The MIL illuminates during a bulb test and a system test.
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A DTC will be stored if a MIL is requested by the diagnostic.
MIL ILLUMINATION
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The MIL will illuminate with ignition ON and the engine not running.
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The MIL will turn OFF when the engine is started.
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The MIL will remain ON if the self-diagnostic system has detected a malfunction.
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The MIL may turn OFF if the malfunction is not present.
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If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated so long as the ignition is ON.
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If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition is cycled OFF, then ON.
DIAGNOSTIC AIDS
If the problem is intermittent, Refer to Intermittent Conditions. See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Intermittent
Conditions
TEST DESCRIPTION
Steps 1-6
The number below refers to the step numbers on the diagnostic table.
2. The step determines if the condition is with the MIL control circuit or the PCM.
