Liberty, Wrangler, 1997-2005

Crankshaft Position Sensor

Print

Operation



2.4L Engine

The Crankshaft Position (CKP) sensor is mounted into the right front side of the cylinder block. It is positioned and bolted into a machined hole.

Engine speed and crankshaft position are provided through the CKP (Crankshaft Position) sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing.

The sensor is a Hall effect device combined with an internal magnet. It is sensitive to steel within a certain distance. A tone wheel (target wheel) is a part of the engine crankshaft. This tone wheel has sets of notches at its outer edge. The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.

Click image to see an enlarged view

Fig.

3.7L V6

The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block. It is positioned and bolted into a machined hole.

Engine speed and crankshaft position are provided through the CKP (Crankshaft Position) sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing.

Click image to see an enlarged view

Fig.

The sensor is a Hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it. A tone wheel (target wheel) is bolted to the engine crankshaft. This tone wheel has sets of notches at its outer edge. The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.

Click image to see an enlarged view

Fig.

4.0L

The Crankshaft Position Sensor (CKP) is mounted to the transmission bellhousing at the left/rear side of the engine block. Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the powertrain control module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing. The sensor is a Hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.

On 4.0L 6-cylinder engines, the flywheel/drive plate has 3 sets of four notches at its outer edge. The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM. For each engine revolution there are 3 sets of four pulses generated.

The trailing edge of the fourth notch, which causes the pulse, is four degrees before top dead center (TDC) of the corresponding piston. The engine will not operate if the PCM does not receive a crankshaft position sensor input.

Click image to see an enlarged view

Fig.



Click image to see an enlarged view

Fig.

Removal & Installation



2.4L Engines

The Crankshaft Position (CKP) sensor is mounted into the right front side of the cylinder block. It is positioned and bolted into a machined hole.

  1. Disconnect sensor electrical connector.
  2.  
  3. Remove sensor bolt.
  4.  
  5. Carefully twist sensor from cylinder block.
  6.  
  7. Check condition of sensor O-ring.
  8.  

Ti ynstall:

  1. Clean out machined hole in engine block.
  2.  
  3. Apply a small amount of engine oil to sensor O-ring.
  4.  
  5. Install sensor into engine block with a slight rocking action. Do not twist sensor into position as damage to O-ring may result.
    WARNING
    Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. If sensor is not flush, damage to sensor mounting tang may result.

  6.  
  7. Install mounting bolt and tighten to 28 Nm (21 ft. lbs.) torque.
  8.  
  9. Connect electrical connector to sensor.
  10.  

3.7L
  1. Raise vehicle.
  2.  
  3. Disconnect sensor electrical connector.
  4.  
  5. Remove sensor mounting bolt.
  6.  
  7. Carefully remove sensor from cylinder block in a rocking and twisting action.
  8.  
  9. Check condition of sensor O-ring.

    Click image to see an enlarged view

    Fig.

  10.  

To install:

  1. Clean out machined hole in engine block.
  2.  
  3. Apply a small amount of engine oil to sensor O-ring.
  4.  
  5. Install sensor into engine block with a slight rocking and twisting action.
    WARNING
    Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. If sensor is not flush, damage to sensor mounting tang may result.

  6.  
  7. Install mounting bolt and tighten to 28 Nm (21 ft. lbs.) torque.
  8.  
  9. Connect electrical connector to sensor.
  10.  

4.0L Engine

The Crankshaft Position (CKP) sensor is mounted to the transmission bellhousing at the left/rear side of the engine block. The sensor is adjustable and is attached with one bolt. A wire shield/router is attached to the sensor.

  1. Disconnect sensor pigtail harness (3way connector) from main engine wiring harness.
  2.  
  3. Remove sensor mounting bolt.
  4.  
  5. Remove wire shield and sensor.
  6.  

To install:

New replacement sensors will be equipped with a paper spacer glued to bottom of sensor. If installing (returning) a used sensor to vehicle, a new paper spacer must be installed to bottom of sensor. This spacer will be ground off the first time engine is started. If spacer is not used, sensor will be broken the first time engine is started.

New Sensors: Be sure paper spacer is installed to bottom of sensor. If not, obtain spacer PN05252229.

Used Sensors: Clean bottom of sensor and install spacer PN05252229.

  1. Install sensor into transmission bellhousing hole.
  2.  
  3. Position sensor wire shield to sensor.
  4.  
  5. Push sensor against flywheel/drive plate. With sensor pushed against flywheel/drive plate, tighten mounting bolt to 7 Nm (60 inch lbs.) torque.
  6.  
  7. Route sensor wiring harness into wire shield.
  8.  
  9. Connect sensor pigtail harness electrical connector to main wiring harness.
  10.  

4.7L
  1. Clean out machined hole in engine block.
  2.  
  3. Apply a small amount of engine oil to sensor O-ring.
  4.  
  5. Install sensor into engine block with a slight rocking action. Do not twist sensor into position as damage to O-ring may result.
    WARNING
    Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. If sensor is not flush, damage to sensor mounting tang may result.

  6.  
  7. Install mounting bolt and tighten to 28 Nm (21 ft. lbs.) torque.
  8.  
  9. Connect electrical connector to sensor.
  10.  
  11. Install starter motor.
  12.  

 
label.common.footer.alt.autozoneLogo