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OBD II Basics
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MIL Test
The first step is a bulb test. The vehicle is first checked for a functioning MIL light with the Engine Off. The lane operator will look to see that the MIL light comes on, even briefly,  when the ignition key is first turned toward engine start, but not actually starting the engine.

The second step is to verify that the MIL does not come on with the Engine Running.

After the bulb test, the inspection system will ask the vehicle computer if it has commanded the MIL ON. The vehicle fails the test only if the MIL is commanded on and there is a DTC.
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