The crankshaft fluctuation sensor features a pulse rotor on the front end of the crankshaft and a pickup sensor mounted on the engine adjacent to the rotor, with the PCM utilizing the signal to monitor changes in the crankshaft's rotational speed; if these changes surpass a predetermined limit, a misfire is indicated. To check the sensor, locate the electrical connector at the timing belt end of the engine, ensuring the key is in the OFF position before disconnecting it. An ohmmeter should be connected between the two outer terminals of the connector, with a reading of 1.6 to 3.2 k-ohms indicating proper function; if the reading is outside this range, the sensor needs replacement. Additionally, connecting the ohmmeter between body ground and each of the sensor's outer terminals should show no continuity; if it does, the sensor must be replaced. For replacement, remove the valve cover, crankshaft pulley, and timing belt cover, then disconnect the sensor's electrical connector and remove its mounting bolt, with installation following the reverse order of removal.