Nissan 240SX/Altima 1993-1998 Repair Guide

Crankshaft Position Sensor

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OPERATION



The Crankshaft Position (CKP) sensor is located on the transmission/transaxle housing, facing the gear teeth of the flywheel/flexplate. It detects the fluctuation of the engine revolution. The sensor consists of a permanent magnet, core and coil.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. This changing gap causes the magnetic field near the sensor to change. Due to the changing magnetic field, the voltage from the sensor changes.

The ECM receives this varying voltage signal and detects the fluctuation of the engine revolution. This sensor is not directly used to control the engine system. It is used for the on-board diagnosis of a misfire.

TESTING



  1. Remove the sensor from the engine.
  2.  
  3. Inspect the sensor tip. If damage to the tip is evident, replace the sensor.
  4.  
  5. Measure the resistance between the sensor terminals.
  6.  
  7. Sensor resistance should be 167-204 ohms @ 68°F (20°C) on 240SX and 432-528 ohms @ 77°F (25°C) on Altima.
  8.  
  9. If resistance is not within specification, the sensor may be faulty.
  10.  

REMOVAL & INSTALLATION



The crankshaft position sensor is located on the transmission/transaxle housing facing the gear teeth of the flywheel/flexplate.

  1. Disconnect the sensor electrical harness.
  2.  
  3. Remove the sensor mounting bolts.
  4.  
  5. Remove the sensor from the transaxle/transmission housing.
  6.  

To install:
  1. Install the sensor in the transaxle/transmission housing.
  2.  
  3. Tighten the sensor mounting bolts securely.
  4.  
  5. Connect the sensor electrical harness.
  6.  

 
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