Chrysler Cirrus/Stratus/Sebring/Avenger/Breeze 1995-1998

Crankshaft Position Sensor

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OPERATION



See Figures 1 through 5

The PCM determines what cylinder to fire from the crankshaft position sensor input and the camshaft position sensor input. On 4-cylinder engines, the second crankshaft counterweight has two sets of four timing reference notches, including a 60° signature notch. From the crankshaft position sensor input, the PCM determines engine speed and crankshaft angle (position). On 6-cylinder engines, this sensor is a Hall effect device that detects notches in the flexplate.



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Fig. Fig. 1: Location of the crankshaft position sensor on 2.0L engines



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Fig. Fig. 2: Location of the crankshaft position sensor on 2.4L engines



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Fig. Fig. 3: Timing reference notches on 4-cylinder engines



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Fig. Fig. 4: Location of the crankshaft position sensor on 2.5L engines



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Fig. Fig. 5: Timing reference notches on 2.5L engines

The notches generate pulses from high to low in the crankshaft position sensor output voltage. When a metal portion of the notches line up with the crankshaft position sensor, the sensor output voltage goes low (less than 0.5 volts). When a notch aligns with the sensor, voltage goes high (5.0 volts). As a group of notches pass under the sensor, the output voltage switches from low (metal) to high (notch), then back to low.

If available, an oscilloscope can display the square wave patterns of each voltage pulse. From the width of the output voltage pulses, the PCM calculates engine speed. The width of the pulses represent the amount of time the output voltage stays high before switching back to low. The period of time the sensor output voltage stays high before switching back to low is referred to as pulse width. The faster the engine is operating, the smaller the pulse width on the oscilloscope.

On 4-cylinder engines, the crankshaft position sensor is mounted to the engine block behind the alternator, just above the oil filter. On 6-cylinder engines, the crankshaft position sensor is mounted on the transaxle housing, above the vehicle speed sensor.

TESTING



To test this sensor, you will need the use of an oscilloscope.

Visually check the connector, making sure it is attached properly and that all of the terminals are straight, tight and free of corrosion. Also inspect the notches in the crankshaft (4-cylinder) or flywheel (6-cylinder) for damage, and replace if necessary.

The output voltage of a properly operating crankshaft position sensor switches from high (5.0 volts) to low (0.3 volts). By connecting an oscilloscope to the sensor output circuit, you can view the square wave pattern produced by the voltage swing.

REMOVAL & INSTALLATION



4-Cylinder Engines

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the crankshaft position sensor electrical connector.
  4.  
  5. Unfasten the sensor mounting screw, then remove the sensor from the vehicle.
  6.  

To install:
  1. Install the sensor in the vehicle and secure with the retaining screw. Tighten the retaining screw to 105 inch lbs. (12 Nm).
  2.  
  3. Attach the crankshaft position sensor electrical connector.
  4.  
  5. Connect the negative battery cable.
  6.  

6-Cylinder Engines

See Figures 6

  1. Disconnect the negative battery cable.
  2.  
  3. If necessary for access, remove the speed control servo unit from the left side strut tower.
  4.  
  5. Unfasten the sensor mounting screw, then pull the sensor straight up and out of the transaxle housing.
  6.  

The sensor connector may be attached to the heater tube bracket with a push-on clip. If so, pull the connector from the bracket to free it.

  1. Detach the crankshaft position sensor electrical connector and remove it from the vehicle.
  2.  

To install:


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Fig. Fig. 6: Crankshaft position sensor and spacer

The crankshaft position sensor should be adjustable, which is identifiable by the presence of an elongated mounting hole on the sensor itself. If the sensor removed is being re-installed, clean off the old paper spacer from the sensor face. A new spacer must be mounted on the face before installation. However, if a new crankshaft position sensor is being installed, confirm that a paper spacer is already present.

  1. Install the sensor into the transaxle and push down until it contacts the flexplate. Hold the sensor in position and install the mounting screw. Tighten the sensor mounting screw to 105 inch lbs. (12 Nm).
  2.  
  3. Attach the crankshaft position sensor's electrical connector.
  4.  
  5. Attach the electrical connector to the heater tube bracket.
  6.  
  7. If removed, install the speed control servo unit back into position and tighten the mounting nuts to 80 inch lbs. (9 Nm).
  8.  
  9. Connect the negative battery cable.
  10.  

 
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