| FSM page EF & EC 175 says to check continuity (using and ohm meter) between the two pins of the speed sensor as the speed sensor shaft is rotating and that it should come and go. This is incorrect for the Z32 speed sensor. FSM page EF & EC 17 describes the speed sensor as having a reed switch to produce pulses. This is also incorrect for the Z32 speed sensor. The Z32 speed sensor is like a little electrical generator. It produces an AC wave forming signal as the speed sensor shaft rotates and increases in voltage as the rotation of the speed sensor shaft increases. You check this using a multimeter set to check AC voltage. Although you will see a voltage being produced, the meter does not tell you the oscillation rate, or in other words, the frequency in hertz of the signal being produced. FSM page EF & EC 118 for diagnosing the speed sensor signal has you check for a continuity that will come and go as you check resistance between ECU pin 53 and ground as the speed sensor shaft is rotating. This is correct but does not tell you how this signal is obtained. The speed sensor sends it's signal, a low amplitude alternating current signal that varies in frequency measured in hertz to the gauge cluster and speedometer board. The speedometer board circuitry converts this signal to a digital on or off (zero or 5 volt) signal which is then sent to the ECU. Interruptions to this signal can be either bad wiring (no continuity or a short), a bad speed sensor or a speedometer board that is not working correctly. Although the speed sensor is difficult to remove, the best way to check it is to remove it. Remove the snap ring which secures the gear and remove the gear. Using a drill, place the speed sensor shaft in the drill as you would a drill bit. Connect a multimeter set to check AC voltage to the two speed sensor pins. Hold the speed sensor so only the shaft rotates and increase the drill speed. At high rates of speed you'll see the voltage increase to as much as 8 volts or more. If you see no voltage, intermittent voltage or voltage less than 5 volts with the drill speed on high then the speed sensor is bad.
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