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Home >> Hummer >> 2009 >> H3 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Controls And Fuel - 5.3L - Introduction) >> Description and Operation >> Electronic Ignition System Description >> Camshaft Position (CMP) Sensor
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Camshaft Position (CMP) Sensor

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The sensor detects magnetic flux changes between the four narrow and wide tooth slots on the reluctor wheel. The CMP sensor provides a digital ON/OFF DC voltage of varying frequency per each camshaft revolution. The ECM will recognize the narrow and wide tooth patterns to identify camshaft position, or which cylinder is in compression and which is in exhaust. The information is then used to determine the correct time and sequence for fuel injection and ignition spark events.