Ram Truck 1500, 2500 & 3500 (2006-2008)

Crankshaft Position Sensor

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Operation



3.7L, 4.7L & 5.7lengines

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 also sensitive to steel within a certain distance from it.

A tonewheel is bolted to the engine crankshaft . This tonewheel 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.

5.9L & 6.7L Engines

The Crankshaft Position Sensor (CKP) is the primary engine speed indicator for the engine after the engine is running.

The CKP contains a hall effect device. A rotating, notched target wheel (tonewheel) for the CKP is located behind the engine harmonic balancer. This hall effect device detects notches located on the tonewheel. As the tonewheel rotates, the notches pass the tip of the CKP.

When the leading edge of the tonewheel notch passes the tip of the CKP, the following occurs: The interruption of magnetic field causes the voltage to switch high resulting in a signal of approximately 5 volts.

When the trailing edge of the tonewheel notch passes the tip of the CKP, the following occurs: The change of the magnetic field causes the signal voltage to switch low to 0 volts.

Removal & Installation



3.7L, 4.7L & 5.7L Engines
  1. Raise the vehicle.
  2.  
  3. Disconnect the Crankshaft Position Sensor (CKP) electrical connector.
  4.  
  5. Remove the CKP sensor mounting bolt.
  6.  
  7. Carefully twist sensor from cylinder block.
  8.  
  9. Check condition of sensor O-ring.
  10.  

To install:

  1. Clean out the machined hole in the engine block.
  2.  
  3. Apply a small amount of engine oil to sensor O-ring.
  4.  
  5. Install the CKP 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 21 ft. lbs. (28 Nm).
  8.  
  9. Connect the electrical connector to the CKP sensor.
  10.  
  11. Lower the vehicle.
  12.  

5.9L & 6.7L Engines
  1. Raise and support vehicle
  2.  
  3. Disconnect the electrical connector at the Crankshaft Position Sensor (CKP).
  4.  
  5. Remove the CKP sensor mounting bolt.
  6.  
  7. Remove the CKP sensor.
  8.  

To install:

  1. Position and install CKP sensor to the engine.
  2.  
  3. Install CKP sensor mounting bolt and tighten to 80 in. lbs. (9 Nm).
  4.  
  5. Install the electrical connector to the CKP sensor.
  6.  

Testing



3.7L, 4.7L & 5.7L Engines
  1. Turn the ignition off.
  2.  
  3. Disconnect the CKP Sensor harness connector.
  4.  
  5. Ignition on, engine not running.
  6.  
  7. Measure the voltage on the (F855) 5-volt Supply circuit in the CKP Sensor harness connector.
  8.  
  9. If the voltage is not between 4.5-5.2 volts. Repair the open or short to ground in the (F856) 5-volt Supply circuit.

    Click image to see an enlarged view

    Fig. Crankshaft sensor electrical connector 3.7L- 4.7L-5.7L engines

  10.  

5.9L & 6.7L Engines
  1. Disconnect the CKP sensor harness connector.
  2.  
  3. Check connectors and clean or repair as necessary.
  4.  
  5. Measure the resistance between the (K824) 5-volt supply circuit and the (K24) signal circuit of the sensor.
  6.  
  7. If the resistance is not between 900-1100 ohms, replace the crankshaft sensor.

    Click image to see an enlarged view

    Fig. Crankshaft position sensor electrical connector

  8.  

 
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