Liberty, Wrangler 2006-2007

Camshaft Position Sensor

Print

Description & Operation



The CMP sensor contains a hall effect device referred to as a sync signal generator. The CMP sensor target wheel is equipped with a cutout (notch) around 180 ° of the wheel. The CMP detects this cutout every 180 ° of camshaft gear rotation. Its signal is used in conjunction with the Crankshaft Position Sensor (CKP) to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.

When the leading edge of the target wheel cutout enters the tip of the CMP, the interruption of magnetic field causes the voltage to switch high, resulting in a sync signal of approximately 5 volts. When the trailing edge of the target wheel cutout leaves the tip of the CMP, the change of magnetic field causes the sync signal voltage to switch low to 0 volts.

Removal & Installation



2.4L Engines
  1. Disconnect electrical connector at CMP sensor.
  2.  
  3. Remove 2 sensor mounting bolts.
  4.  
  5. Remove sensor from cylinder head by sliding towards rear of engine.
  6.  

To install:

  1. Remove plastic, upper timing belt cover (timing gear cover) by removing 3 bolts. Before attempting to remove cover, remove electrical connector from Engine Coolant Temperature (ECT) sensor. This will prevent damage to sensor.
  2.  
  3. Rotate (bump over) engine until camshaft timing gear and target wheel (tone wheel) are positioned and aligned to face of sensor.
    WARNING
    If gear and tone wheel are not properly positioned, damage to both sensor and target wheel will occur when attempting to start engine. Face of sensor MUST be behind target wheel while adjusting.

  4.  
  5. Position sensor to cylinder head and install 2 sensor mounting bolts finger tight.
  6.  
  7. Set air gap between rear of target wheel and face of sensor to .030. This can best be accomplished using an L-shaped, wire-type spark plug gapping gauge. A piece of .030 brass shim stock may also be used.
  8.  
  9. Gently push sensor forward until it contacts gapping gauge. Do not push hard on sensor. Tighten 2 sensor mounting bolts.
    WARNING
    After tightening sensor mounting bolts, recheck air gap and adjust as necessary. Retorque bolts.

  10.  
  11. Install upper timing belt cover and 3 bolts.
  12.  
  13. Connect electrical connector to ECT sensor.
  14.  
  15. Connect electrical connector to CMP sensor.

    Click image to see an enlarged view

    Fig. CMP sensor and mounting on 2.4L engines

  16.  

3.7L Engine
  1. Disconnect electrical connector at CMP sensor.
  2.  
  3. Remove sensor mounting bolt.
  4.  
  5. Carefully remove sensor from cylinder head in a rocking and twisting action. Twisting sensor eases removal.
  6.  

To install:

  1. Check condition of sensor O-ring.
  2.  
  3. Clean out machined hole in cylinder head.
  4.  
  5. Apply a small amount of engine oil to sensor O-ring.
  6.  
  7. Install sensor into cylinder head with a slight rocking and twisting action.
    WARNING
    Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder head. If sensor is not flush, damage to sensor mounting tang may result.

  8.  
  9. Install mounting bolt and tighten.
  10.  
  11. Connect electrical connector to sensor.

    Click image to see an enlarged view

    Fig. Showing the CMP sensor (3) and mounting bolt (2) on the right front cylinder head (1) on the 3.7L engine

  12.  

4.0L Engine
  1. Disconnect electrical connector at CMP sensor.
  2.  
  3. Remove 2 sensor mounting bolts.
  4.  
  5. Remove sensor from oil pump drive.
  6.  

To install:

  1. Install sensor to oil pump drive.
  2.  
  3. Install 2 sensor mounting bolts and tighten to 15 inch lbs. (2 Nm).
  4.  
  5. Connect electrical connector to CMP sensor.

    Click image to see an enlarged view

    Fig. Identifying the location of the CMP sensor (2) and related components on the 4.0L engine: oil filter (1); clamp bolt (3); hold-down clamp (4); mounting bolts (5); electrical connector (6)

  6.  

Testing



  1. Inspect the CMP sensor for correct installation. Remove the CMP sensor from the engine and inspect the sensor O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, replace the CMP sensor.
  2.  
  3. Engage the CMP sensor harness connector to the CMP sensor.
  4.  
  5. Connect the scan tool to the diagnostic connector.
  6.  
  7. With the ignition ON , engine off observe the CMP Active counter parameter on the scan tool.
  8.  
  9. Pass a flat steel object across the tip of the sensor repeatedly. The CMP Active counter parameter should increment with each pass of the steel object.
  10.  
  11. If the parameter does not increment, replace the CMP sensor.
  12.  

 
label.common.footer.alt.autozoneLogo