Camshaft Position Sensor: Description and Operation

Camshaft Position (CMP) Sensor:

The Camshaft Position (CMP) Sensor works in conjunction with a single tooth reluctor wheel on the bank 2 intake camshaft. The ECM pulls up the CMP sensor signal circuit to 12 volts and monitors this voltage. As the reluctor wheel tooth rotates past the sensor, the sensors internal circuitry pulls the signal circuit to ground, creating a square wave signal used by the ECM. The reluctor wheel tooth covers 180 degrees of the camshaft circumference. This causes the CMP signal voltage to transition once per crankshaft revolution. This signal, when combined with the Crankcase Position (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. Note that as long as the CKP signal is available, the engine can start even if there is no CMP sensor signal. The ECM will default to non-sequential fuel injector operation. The DTC P0340-CMP Sensor Circuit indicates that the ECM has detected a CMP system fault.