GM Corvette 1984-1996 Repair Guide

Camshaft Position Sensor

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OPERATION



The 5.7L (VIN J) engine is the only engine which uses a Camshaft Position (CMP) sensor.

The PCM uses the CMP sensor to determine the position of the No. 1 piston during its power stroke. This signal is used by the PCM to calculate fuel injection mode of operation.

If the cam signal is lost while the engine is running, the fuel injection system will shift to a calculated fuel injected mode based on the last fuel injection pulse, and the engine will continue to run.

TESTING



VIN J Engines

See Figure 1

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

The camshaft position sensor used on these engines is a 3-wire, Hall effect type sensor. The sensor requires power and ground to function. When performing this test, backprobe all connectors.

  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. With the ignition in the ON position, check the sensor voltage using an oscilloscope. When the starter is briefly operated, a square wave pattern, alternating from 0-12 volts should be seen at terminal B. If the voltage is within specification, the sensor is functional
  4.  
  5. If the sensor voltage is not within specifications, use a DVOM to check terminal A for battery positive (B+). If battery positive (B+) is not present, check the circuit continuity and repair as necessary.
  6.  
  7. If battery positive (B+) is present at terminal A, check terminal C for proper ground. If ground is not present check the circuit for continuity and repair as necessary.
  8.  
  9. If the sensor and circuits are functional, the PCM may be faulty.
  10.  

REMOVAL & INSTALLATION



VIN J Engine

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. If necessary, remove the intake manifold.
  4.  
  5. Detach the CMP sensor electrical connector.
  6.  
  7. Clean the area around the CMP sensor to avoid getting debris in the engine.
  8.  
  9. Remove the CMP sensor retaining bolt, then remove the sensor from the engine.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Location of the Camshaft Position (CMP) sensor-5.7L (VIN J) engine

To install:
  1. Install the CMP sensor and retaining bolt. Tighten the bolt to 18 ft. lbs. (25 Nm).
  2.  
  3. Attach the CMP sensor electrical connector.
  4.  
  5. Install the intake manifold.
  6.  
  7. Connect the negative battery cable.
  8.  

 
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