Q: What is the function and testing procedure for the crankshaft position sensor on Nissan Quest?A: CPS is located on transaxle bellhousing to observe the variation of the crankshaft speed with the help of a permanent magnet, core and coil. The altering difference results into a change of the magnetic field in proximity with the sensor; this in turn alters the voltage to PCM signal. This sensor is used exclusively as the engine's light-on instrument to indicate a misfire condition. To test the sensor, first remove the electrical connector and probe the two terminals of the crank shaft sensor; the should register between 432 to 528 ohms. If the above resistance values are as specified then there could be open circuits in the wiring harness or the wiring could be damaged. Although the terminals on the sensor may be hard to reach because of the crossover exhaust manifold check tube, it may be easier to disconnect the sensor first before undertaking the test. For replacement, unbolt and slide out the heat needed retaining nut and the heat shield; disconnect the electrical connector from the sensor; and then unbolt and pull the sensor from the bellhousing. Removal is the undoing of installation, and therefore the latter is done in reverse order.