The crank sensor is basically a coil inside. First inspect the wiring and connector to see whether there's any damage. You can measure the coil with an ohmmeter and you should get some low resistance value and not high resistance or open circuit. Next, check the gap between the sensor and teeth of the crank pulley, the gap should be between 0.5 to 1.0 mm. The signal from the CAS is of the form of sine (sinusoidal) wave when the teeth pass through the sensor interrupting the magnetic field. There is a longer signal interruption per revolution when the sensor passes over the two missing teeth area of the crank pulley. Normally, one should use a oscilloscope to look at the pattern of the signal. But you can use a voltmeter and set it to AC volts (~5 volts range if needed). You should get some AC voltage when the crank pulley turns. The page from 24V manual below has some additional information. It said you should get about 0.5V to 100V (page is fuzzy and I believe it makes more sense to be 1.00V). You can measure at the sensor connector but if you measure at the ECU connector (pins 23 and 25) you can also determine whether the wires all the way to the ECU is any good.How do I test the crank sensor? Can I disconnect it at the connector and test it with a meter while turning over the motor?