Mercury Villager Nissan Quest 1997-2000

Camshaft Position Sensor

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OPERATION

The camshaft position sensor (CMP) is mounted inside of the distributor housing, and is part of the distributor assembly. It consists of a rotor plate, a photo diode, and light emitting diodes (LEDs). The rotor plate has 360 slits which generate a 1° signal, and 6 slits which generate a 120° signal. As the distributor rotates, signals are generated as the rotor plate passes between the photo diode and the LEDs. The signals are sent to the PCM to indicate engine speed and piston position. The PCM uses the information to control the fuel injection, ignition timing, and other functions.

TESTING
1993-95 Vehicles
  1. Remove the distributor from the engine. Leave the distributor wiring harness connected.
  2.  
  3. Using a voltmeter set to the DC range, connect the negative lead of a voltmeter lead to the negative battery terminal.
  4.  
  5. Insert the positive lead probe into the back of the distributor connector in pin 3.
  6.  
  7. With the ignition switch on and the engine OFF , rotate the distributor by hand and observe the voltmeter reading. The reading should fluctuate between 0 and 5 volts.
  8.  
  9. Disconnect the positive voltmeter lead from pin 3 and connect it to pin 4 of the connector.
  10.  
  11. Rotate the distributor by hand and observe the voltmeter reading. The reading should fluctuate between 0 and 5 volts.
  12.  
  13. If the voltage is not within specifications, the sensor may be faulty.
  14.  



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Fig. Voltmeter connections for camshaft position sensor testing-1993-95 vehicles

1996-98 Vehicles
  1. Remove the distributor from the engine. Leave the distributor wiring harness connected.
  2.  
  3. Using a voltmeter set to the DC range, connect the negative lead of a voltmeter lead to the negative battery terminal.
  4.  
  5. Insert the positive lead probe into the back of the distributor connector in pin 2.
  6.  
  7. With the ignition switch on and the engine OFF , rotate the distributor by hand and observe the voltmeter reading. The reading should fluctuate between 0 and 5 volts.
  8.  
  9. Disconnect the positive voltmeter lead from pin 2 and connect it to pin 3 of the connector.
  10.  
  11. Rotate the distributor by hand and observe the voltmeter reading. The reading should fluctuate between 0 and 5 volts.
  12.  
  13. If the voltage is not within specifications, the sensor may be faulty.
  14.  



Click image to see an enlarged view

Fig. Voltmeter connections for camshaft position sensor testing-1996-98 vehicles

1999-00 Vehicles

On 1999-00 vehicles, the camshaft position sensor must be checked with the engine running. If a no start condition is encountered, observe the MIL. With the ignition switch on and the engine off, the MIL should be illuminated. If the camshaft position sensor is functioning, the MIL should go out when cranking the engine.

  1. Run the engine until it reaches normal operating temperature. Leave the engine running.
  2.  
  3. Using a voltmeter set to the DC range, connect the negative lead of a voltmeter lead to the negative battery terminal or chassis ground.
  4.  
  5. Connect the positive voltmeter lead to the back of the PCM electrical connector in terminal 44.
  6.  
  7. Observe the voltmeter reading. The reading should be 0.3-0.5 volts.
  8.  
  9. Disconnect the positive voltmeter lead from terminal 44, and connect it to terminal 49.
  10.  
  11. Observe the voltmeter reading. The reading should be approximately 2.5 volts.
  12.  
  13. Perform steps 3 through 6 with the engine at 2,000 rpm with the transaxle in park. The voltage readings should be the same.
  14.  
  15. If the observed voltages are not within specifications, the sensor may be faulty.
  16.  

REMOVAL & INSTALLATION

The camshaft position sensor is part of the distributor assembly, and must be replaced as a unit. Please refer to Engine Electrical, Distributor Ignition System, Distributor, Removal and Installation for the procedure.

 
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