Camshaft Position Sensor: Description and Operation

The Camshaft Position (CMP) sensor detects a single tooth reluctor wheel on the Bank 2 Intake camshaft. The ECM pulls up the CMP sensor signal circuit to 5 volts and monitors this voltage. As the reluctor wheel tooth rotates past the sensor, the sensor's internal circuitry pulls the signal circuit to ground, creating a square wave signal used by the ECM. The CMP signal voltage transitions once per every two crankshaft revolutions. This signal, when combined with the CKP sensor signal, enables the ECM to determine exactly which cylinder is on a firing stroke. The ECM can then properly synchronize the ignition system, the fuel injectors and the knock control. As long as the CKP signal is available, the engine can start even if there is not CMP signal. The ECM will default to non-sequential fuel injector operation.