K 3500 Truck 4WD V8-6.6L DSL Turbo VIN 1 (2001)
Malfunction Indicator Lamp: Testing and Inspection
Malfunction Indicator Lamp (MIL) Always On
CIRCUIT DESCRIPTION
The battery positive voltage is supplied directly to the Malfunction Indicator Lamp (MIL). The Engine Control Module (ECM) turns the MIL ON by
grounding the MIL control circuit.
MIL OPERATION
The Malfunction Indicator Lamp (MIL) is located on the instrument panel.
MIL FUNCTION
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The MIL informs the driver that a malfunction has occurred. The vehicle should be serviced as soon as possible.
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The MIL illuminates during a bulb test, and during a system test.
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A DTC will be stored if the diagnostic test requests a MIL.
MIL ILLUMINATION
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The MIL will illuminate with ignition switch ON, and with the engine not running.
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The MIL will turn OFF when the you start the engine.
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The MIL will remain ON if the self-diagnostic system detects 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 if the ignition switch is ON.
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If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, and cycled ON again.
TEST DESCRIPTION
Steps 1-8
The number below refers to the step number on the diagnostic table.
3. The step determines if the condition is with the MIL control circuit or the ECM.
