GM Corvette 1984-1996 Repair Guide

Crankshaft Position Sensor

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OPERATION



See Figures 1 and 2

The CKP sensor provides a signal through the ignition module which the PCM uses as a reference to calculate RPM and crankshaft position.



Click image to see an enlarged view

Fig. Fig. 1: View of the Crankshaft Position (CKP) sensor used on VIN J engines



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Fig. Fig. 2: Crankshaft and CKP sensor relation-VIN J engine

TESTING



The best method to test this sensor is by using an oscilloscope.

  1. Visually check the connector, making sure it is connected properly and all of the terminals are straight, tight and free of corrosion.
  2.  
  3. If a Tech 1® or equivalent scan tool is available, scan the CKP or RPM parameter while cranking the engine. If signals are indicated, the CKP sensor is functioning properly.
  4.  
  5. If the scan tool is not available, use a digital multimeter set to the ohms setting, then check the resistance across the sensor terminals. The resistance should measure about 500-1200 ohms at about 70° F. The resistance will vary with temperature.
  6.  

This test must be performed with the ignition

ON and the engine OFF .

  1. Using a thin piece of steel, check the tip of the sensor to see if it is magnetized.
  2.  
  3. Using a digital multimeter set to the millivolts AC scale, connect the test probes to the sensor.
  4.  
  5. Rotate the reluctor ring to activate the sensor signal. Use the starter to crank the engine.
  6.  
  7. Voltage should be seen as the reluctor ring is rotated. If the reluctor is rotated quickly, a signal of at least 200 millivolts AC should be seen.
  8.  
  9. If the sensor and circuits are functional, the PCM may be faulty.
  10.  

REMOVAL & INSTALLATION



VIN J Engine

See Figure 3

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Unfasten any necessary retainers, then remove CKP sensor shield.
  6.  
  7. Detach the CKP sensor electrical connector.
  8.  
  9. Unfasten the CKP sensor mounting bolt, then remove the sensor from the vehicle.
  10.  
  11. If equipped, remove the sensor shim.
  12.  



Click image to see an enlarged view

Fig. Fig. 3: The CKP sensor is mounted in the lower right side of the engine block, between cylinders 4 & 6, just above the oil pan

To install:
  1. Lubricate the CKP sensor O-ring with clean engine oil. If used, install the sensor shim.
  2.  
  3. Position the CKP sensor and install the mounting bolt. Tighten the bolt to 71 inch lbs. (8 Nm).
  4.  
  5. Attach the sensor electrical connector.
  6.  
  7. Install the CKP sensor shield, securing with the retainers as necessary.
  8.  
  9. Carefully lower the vehicle, then connect the negative battery cable.
  10.  

 
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