There are three main types of camshaft position sensor: the magnetoresistive sensor, the Hall Effect switching device and the magnetic sensor. The camshaft position sensor's main function is to signal the vehicle's on-board computer with the camshaft's rotational speed and position. The computer can then determine various engine functions related to the fuel injection system. A malfunctioning camshaft position sensor may cause the engine to shut off intermittently, or misfire and/or hesitate on acceleration. It may also cause the on-board computer to illuminate the "Check Engine" light and set a problem code that a dealer service department can read with a diagnostic scanner tool. This process should only be undertaken by someone with solid automotive experience and knowledge.
Turn the ignition on but do not start the engine. Raise the hood and locate the camshaft position sensor attached to the engine block.
Back-probe the camshaft sensor's electrical terminal by inserting a straight pin, T-pin or meter probe into the back of the electrical connection marked SIG; push the pin in until it contacts the internal wire. Repeat this procedure on the terminal marked GND; do not allow the pins to touch. Place the positive (red) probe of a voltmeter onto the pin marked SIG, and the negative (black) probe to the pin marked GND.
Have an assistant attach a breaker bar and socket to the nut that secures the crankshaft pulley to the engine block and slowly crank the engine by turning the breaker bar clockwise by hand.
Take a reading as the engine is cranked. The voltmeter should show a pulsing voltage from 0 to 5.0 volts. If the voltage remains at zero without pulsing the sensor is not receiving an electrical input from the on-board computer. If the voltage remains at a steady 5.0 volts without pulsing, most likely the sensor is malfunctioning.
Turn the ignition on but do not start the engine.
Back-probe the sensor's electrical connection as described in Section 1, Step 2 above. Place the positive (red) probe of an oscilloscope or graphing multimeter onto the pin marked SIG, and the negative (black) probe to the pin marked GND.
Have an assistant attach a breaker bar and socket to the front of the crankshaft pulley as described in Section 1, Step 3 and slowly crank the engine clockwise by hand.
Take a reading. The oscilloscope or graphing multimeter should show a sign or rounded wave form with a minimum of 2.0 volts peak-to-peak. A voltage signal lower than this indicates the sensor is most likely malfunctioning.