Crankshaft Position Sensor: Description and Operation

TDC/CRANK Sensor:

The TDC/CRANK sensor, found inside of the distributor housing, consists of the TDC sensor rotor, CRANK sensor rotor, their associated pick-up coils, and a common shaft that is directly coupled to the camshaft. Because the shaft is coupled to the camshaft both sensors turn in time with the engine. As the teeth on the sensors break the flux lines of their respective pick-up coils a voltage pulse is generated. These pulses are the input signal to the ECU.

The CRANK sensor detects engine RPM and is also a primary input signal to the ECU for determining fuel injection timing and ignition of each cylinder. The TDC determines ignition timing at start-up (cranking) and when crank angle signal is abnormal.