Operation

OPERATION





The Crankshaft Position Sensor (CKP) (5) is the primary engine speed indicator for the engine after the engine is running.






The CKP contains a hall effect device. A rotating, notched target wheel (tonewheel) (3) for the CKP is attached to the engine harmonic balancer (2). This hall effect device detects notches located on the tonewheel. As the tonewheel rotates, the notches pass the tip of the CKP.

When the leading edge of the tonewheel notch passes the tip of the CKP, the following occurs: The interruption of magnetic field causes the voltage to switch high resulting in a signal of approximately 5 volts.

When the trailing edge of the tonewheel notch passes the tip of the CKP, the following occurs: The change of the magnetic field causes the signal voltage to switch low to 0 volts.

The Camshaft Position Sensor (CMP) also provides a signal to the Engine Control Module (ECM) at all times when the engine is running. The ECM uses this CMP information primarily on engine start-up. Once the engine is running, the ECM uses the CMP as a backup sensor for engine speed.