LaCrosse 2006-2007

Camshaft Position Sensor

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Description & Operation



The Camshaft Position (CMP) sensor is triggered by a notched reluctor wheel built onto the camshaft sprocket. The CMP sensor provides four signal pulses every camshaft revolution. Each notch, or feature of the reluctor wheel, is of a different size which is used to identify the compression stroke of each cylinder and to enable sequential fuel injection. The CMP sensor is connected to the PCM by the following circuits:



A 5-volt circuit
 
A low reference circuit
 
A signal circuit
 

Removal & Installation



3.6L Engine
Bank 1 (Right Side) Exhaust
  1. Turn the ignition OFF.
    NOTE
    Do not remove the Engine Control Module (ECM) from the ECM bracket. Do not remove the ECM redundant ground wire from the ECM.

  2.  
  3. Remove the ECM bracket bolts and reposition the ECM bracket in order to provide access.
  4.  
  5. Remove the Camshaft Position (CMP) sensor electrical connector.
  6.  
  7. Remove the CMP sensor bolt.
  8.  
  9. Remove the CMP sensor.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor, exhaust, bank 1 (right side)-3.6L engine

  10.  

To install:

  1. Install the CMP sensor.
  2.  
  3. Install the CMP sensor bolt. Tighten the CMP sensor bolt to 89 inch lbs. (10 Nm).
  4.  
  5. Install the CMP sensor electrical connector.
  6.  
  7. Install the ECM bracket with the ECM.
  8.  

Bank 1 (Right Side) Intake
  1. Turn the ignition OFF.
  2.  
  3. Remove the Camshaft Position (CMP) sensor electrical connector.
  4.  
  5. Remove the CMP sensor bolt.
  6.  
  7. Remove the CMP sensor.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor, intake, bank 1 (right side)-3.6L engine

  8.  

To install:

  1. Install the CMP sensor.
  2.  
  3. Install the CMP sensor bolt. Tighten the CMP sensor bolt to 89 inch lbs. (10 Nm).
  4.  
  5. Install the CMP sensor electrical connector.
  6.  

Bank 2 (Left Side) Exhaust
  1. Turn the ignition OFF.
    NOTE
    Do not disconnect the power steering fluid lines/hoses from the reservoir.

  2.  
  3. Remove the Power Steering (PS) fluid reservoir bolts and reposition the PS fluid reservoir in order to provide access.

    Click image to see an enlarged view

    Fig. Move the Power Steering (PS) fluid reservoir in order to provide access-3.6L engine

  4.  
  5. Remove the Camshaft Position (CMP) sensor electrical connector.
  6.  
  7. Remove the CMP sensor bolt.
  8.  
  9. Remove the CMP sensor.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor, exhaust, bank 2 (left side)-3.6L engine

  10.  

To install:

  1. Install the CMP sensor.
  2.  
  3. Install the CMP sensor bolt. Tighten the CMP sensor bolt to 89 inch lbs. (10 Nm).
  4.  
  5. Install the CMP sensor electrical connector.
  6.  
  7. Install the PS fluid reservoir.
    1. Tighten the PS pump bracket bolt (1) to 80 inch lbs. (9 Nm).
    2.  
    3. Tighten the PS pump bracket bolt (2) to 18 ft. lbs. (25 Nm).
    4.  

  8.  

Bank 2 (Left Side) Intake
  1. Turn the ignition OFF.
    NOTE
    Do not disconnect the power steering fluid lines/hoses from the reservoir.

  2.  
  3. Remove the Power Steering (PS) fluid reservoir bolts and reposition the PS fluid reservoir in order to provide access.

    Click image to see an enlarged view

    Fig. Move the Power Steering (PS) fluid reservoir in order to provide access-3.6L engine

  4.  
  5. Remove the Camshaft Position (CMP) sensor electrical connector.
  6.  
  7. Remove the CMP sensor bolt.
  8.  
  9. Remove the CMP sensor.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor, intake, bank 2 (left side)-3.6L engine

  10.  

To install:

  1. Install the CMP sensor.
  2.  
  3. Install the CMP sensor bolt. Tighten the CMP sensor bolt to 89 inch lbs. (10 Nm).
  4.  
  5. Install the CMP sensor electrical connector.
  6.  
  7. Install the PS fluid reservoir.
    1. Tighten the PS pump bracket bolt (1) to 80 inch lbs. (9 Nm).
    2.  
    3. Tighten the PS pump bracket bolt (2) to 18 ft. lbs. (25 Nm).
    4.  

  8.  

3.8L Engines
  1. Reposition the coolant reservoir hose clamp (1) aside at the radiator overflow fitting.
  2.  
  3. Remove the coolant reservoir hose from the radiator overflow fitting.
  4.  
  5. Disconnect the coolant reservoir hose support retainer from the electrical harness.
  6.  
  7. Remove the coolant reservoir nuts (2) from the shock tower studs.
  8.  
  9. Remove the coolant recovery reservoir (3) from the lower retainer and the shock tower studs.
  10.  
  11. Drain the coolant from the recovery reservoir into a clean container.

    Click image to see an enlarged view

    Fig. Remove the coolant recovery reservoir-3.8L engine

  12.  
  13. Remove the accessory drive belt. Refer to Accessory Drive Belt, removal and installation.
  14.  
  15. Disconnect the electrical connector (2) from the Camshaft Position (CMP) sensor (1).

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor-3.8L engine

  16.  
  17. Remove the CMP sensor bolt.
  18.  
  19. Remove the CMP sensor from the engine front cover.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) sensor bolt removal-3.8L engine

  20.  

To install:

  1. Install the CMP sensor to the engine front cover.
  2.  
  3. Install the CMP sensor bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  4.  
  5. Connect the electrical connector (2) to the CMP sensor (1).
  6.  
  7. Install the accessory drive belt. Refer to Accessory Drive Belt, removal and installation.
  8.  
  9. Install the coolant recovery reservoir (3) to the lower retainer and the shock tower studs.
  10.  
  11. Install the nuts (2) to the shock tower studs. Tighten the nuts to 29 inch lbs. (3 Nm).
  12.  
  13. Lubricate the reservoir hose with clean water. Route the hose to the radiator overflow neck fitting.
    NOTE
    The hose end must be flush against the radiator filler neck. Seat the clamp squarely between the radiator filler neck and the flared end of the fitting.

  14.  
  15. Install the coolant reservoir hose (1) to the radiator overflow fitting.
  16.  
  17. Connect the coolant reservoir hose support retainer to the electrical harness.
  18.  
  19. Position the coolant reservoir hose clamp to the radiator overflow fitting.
  20.  
  21. Fill the coolant recovery reservoir to the proper level.
  22.  

Testing





Click image to see an enlarged view

Fig. CMP sensor connector end view (all CMP sensor connectors)-3.6L engine



Click image to see an enlarged view

Fig. CMP sensor connector end view-3.8L engine

During normal operation the PCM controls all ignition functions. If either the Crankshaft Position (CKP) or Camshaft Position (CMP) sensor signal is lost, the engine will continue to run because the PCM will default to a limp home mode using the remaining sensor input. Diagnostic trouble codes are available to accurately diagnose the ignition system with an OBD2 scan tool.

  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.  

 
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