Genuine Nissan Maxima Crankshaft Position Sensor

Nissan Maxima Crankshaft Position Sensor Parts Questions & Answers

• Crankshaft Position Sensor
  23731-31U10
  Q: How to diagnosing and replace the crankshaft position (CKP) sensors on Nissan Maxima?

  A: Between 1995 and 1999, two CKP REF and CKP POS crankshaft sensors were used while from 2000 production, only CKP POS sensor is employed. Located at the front of the engine, beneath the crankshaft pulley, the CKP REF sensor identifies spaces around the driving pulley sensor ring that correspond to each cylinder's top dead center (TDC), giving a 120-degree signal. On older cars, the CKP POS sensor resides over the oil pan section of aluminum near transaxle bellhousing whereas in later models such as those made from 2005 onwards, it is positioned at the front of an engine compartment. The flywheel/driveplate gear teeth gaps are recognized with a one-degree signal by CKP POS sensor that determines crankshaft speed. Both of them are provided with a permanent magnet, coil and core where changes in gap result in variation in their magnetic field around the sensor thus altering voltage signal sent to Powertrain Control Module (PCM). These signals by these sensors influence ignition timing, fuel synchronization and detection of any misfire within an engine. To perform this test on a CKP REF sensor, disconnect its electrical connector; then using an ohmmeter check resistance across its two terminals. At temperature between 68 degrees Fahrenheit (20 degrees Celsius) and so on; this should give you a range of about 470 to 570 ohms. If resistance readings are not correct then a new sensing element is necessary. If however resistance readings show as correct then inspect wiring harness for open circuit from PCM or any physical damage to harness itself. Additionally, ensure continuity into ground through black wire on harness connector. When both sensing device and cable assembly test out well further diagnostic work must be performed on PCM by an authorized repair shop or dealer service department. With regard to a CKP POS sensor remove its electrical connector first before switching on the ignition key. Using a voltmeter, measure battery voltage at the Red wire terminal of the harness connector. In case power is missing verify whether there is any problem from the battery to ECCS relay and remember to check fuses as well before looking into ECCS relay that will guide you on how to do circuit checks between it and the sensor. Also, ensure 5.0 volts in white wire terminal. If not then inspect PCM to sensor connector circuit. Providing it is okay, ask dealer service department or another authorized shop for PCM test. Furthermore, check if there is closing of the black wire terminal to ground. For further investigation into CKP POS sensor; remove sensor after detaching ignition key and reconnect electrical connector from sensor afterwards. Using a suitable probe, backprobe white wire terminal of sensor connector by attaching positive lead of a voltmeter to probe while negative lead is connected to a suitable engine ground point. Turn key on then touch momentarily tip of the sensing device with a piece of metallic material such as screwdriver after which remove it quickly. When metal object touches this point voltmeter should show 5.0 volts immediately dropping down to zero when object is removed again. Otherwise replace this sensing unit if its behavior does not go according to what has been described above. Note that if all wiring along with PCM are functioning properly in rare cases when all these parts are working correctly but system keeps setting diagnostic trouble code then flywheel/driveplate should be checked for broken teeth or teeth that have come off completely. To start replacing CKP, disconnect its electrical connector from the sensor followed by removing the CKP retaining bolt and taking out a sensing device itself from its position at last installation process must be performed in reverse order of removal steps made during disassembly procedure for reconditioning or dismantling purpose.