Crank Position Sensor (CKP) (Tech Tip)

Crank Position Sensor (CKP) to indicate when of cylinders reaches TDC (top dead center). It consists of a pulse ring on the crank shaft and a probe with a permanent magnet and a coil wire at its tip. As the crankshaft turns the sudden change in the magnetic flux causes a voltage signal to the produced in the coil wound around the magnet. The CKP provides a reference point for the ECM to create the sparks, timing advance, injector pulses. Cam Position Sensor is relayed through ECM and is used to identify which cylinder is approaching TDC and which ignition coil should be fired, which fuel injector should be injected fuel.

Symptom of Crank Position Sensor Fail: Engine crank but no start, no spark or no injector pulse.



Scan tools provide the best noninvasive method for diagnosing a cranking no start condition. Scan for any crank sensor related code is stored in ECM such P0335, P0336 or more. Second watch the scanner data displays any Engine RPM or speed is displayed during cranking, if it shows RPM signal usually CKP is producing a valid signal is working. If No RPM signal most likely the crank sensor is bad or control circuit failure. Another way connect a voltmeter to beside ignition coil circuit if the voltage pulls down from (positive) B+ during cranking, the CKP is triggering the ignition module or ECM, If the CKP is not triggering spark, possible the caused is Crank Position Sensor, Ignition Control Module, or ECM circuit.