The camshaft position sensor generates pulses at TDC of the piston of the 1st and 4th cylinders in the compression stroke, based on which the ECM unit determines the fuel injection sequence.
The crankshaft speed sensor provides the ECM with information about the crankshaft rotation angle (piston position). Based on the output signal information from this sensor, the ECM calculates the engine speed and crankshaft position.
(Information is taken from a thematic website: «hyundaibook.ru»)