Cobalt 2006-2008, G5 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



2.0L Engines


Click image to see an enlarged view

Fig. Remove the accessory drive belt tensioner-2.0L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the accessory drive belt tensioner:
    1. Remove the accessory drive belt.
    2.  
    3. Remove the drive belt tensioner bolts.
    4.  
    5. Remove the drive belt tensioner.

      Click image to see an enlarged view

      Fig. Remove the underhood junction block-2.0L engine

    6.  

  4.  
  5. Remove the underhood junction block.
  6.  
  7. Remove the cover (2) from the underhood electrical center.
  8.  
  9. Remove the underhood positive battery terminal lug (4).
    NOTE
    Take note of the positioning of the positive battery cables before disconnecting the cables.

  10.  
  11. Disconnect the positive battery cables (5) from the underhood electrical center.
    NOTE
    The underhood electrical center bolts (3) are retained in the electrical center.

  12.  
  13. Loosen all of the underhood electrical center bolts (3).
  14.  
  15. Remove the underhood electrical center (1) from the vehicle.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) Sensor location-2.0L engine

  16.  
  17. Disconnect the electrical connector from the Camshaft Position (CMP) sensor.
  18.  
  19. Remove the CMP sensor studs.
  20.  
  21. Remove the CMP sensor.
  22.  

To install:

Click image to see an enlarged view

Fig. The crankshaft damper-to-front cover timing marks aligned to show TDC for piston number 4-2.0L engine

  1. Rotate the crankshaft until number 4 piston is at Top Dead Center (TDC) on the compression stroke. Refer to the crankshaft damper-to-front cover timing marks.
  2.  
  3. Install the NEW camshaft position sensor housing seal.

    Click image to see an enlarged view

    Fig. Align the timing mark on the housing with the timing mark on the hex shaft-2.0L engine

  4.  
  5. Align the timing mark on the housing with the timing mark on the hex shaft.
  6.  
  7. Install the camshaft position sensor housing.
  8.  
  9. Install the camshaft position sensor housing studs. Tighten the studs to 16 ft. lbs. (22 Nm).
  10.  
  11. Install the underhood junction block:
    1. Position the underhood electrical center (1) to the vehicle.
    2.  
    3. Tighten all of the underhood electrical center bolts (3). Tighten the bolts to 89 inch lbs. (10 Nm).
    4.  
    5. Connect the positive battery cables (5) to the underhood electrical center.
    6.  
    7. Install the underhood positive battery terminal lug (4). Tighten the terminal lug to 133 inch lbs. (15 Nm).
    8.  
    9. Install the cover (2) to the underhood electrical center.
    10.  

  12.  
  13. Install the accessory drive belt tensioner.
  14.  
  15. Install the accessory drive belt tensioner bolts. Tighten the drive belt tensioner bolts to 33 ft. lbs. (45 Nm).
  16.  
  17. Install the accessory drive belt.
  18.  
  19. Connect the negative battery cable.
  20.  

2.2L Engine-Intake
  1. Remove the engine oil fill cap.
  2.  
  3. Grasp the intake manifold cover by the lower right inboard corner and pull up to disengage the cover from the stud.
  4.  
  5. Grasp the intake manifold cover by the upper left corner and pull up to disengage the cover from the stud.
  6.  
  7. Remove the intake manifold cover.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) Sensor location for intake-2.2L & 2.4L engine

  8.  
  9. Disconnect the engine wiring harness electrical connector from the Intake Camshaft Position (CMP) sensor.
  10.  
  11. Remove the CMP sensor bolt.
  12.  
  13. Remove the CMP sensor.
  14.  

To install:


NOTE
Inspect the CMP sensor for damage, replace as necessary.

  1. Lubricate the CMP sensor O-ring seal with clean engine oil.
  2.  
  3. Install the CMP sensor.
  4.  
  5. Install the CMP sensor bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  6.  
  7. Connect the engine wiring harness electrical connector to the intake CMP sensor.
  8.  
  9. Place the intake manifold cover onto the engine over the studs.
  10.  
  11. Push down on the intake manifold cover directly over the lower right stud in order to engage the cover to the stud.
  12.  
  13. Push down on the intake manifold cover directly over the upper left stud in order to engage the cover to the stud.
  14.  
  15. Install the engine oil fill cap.
  16.  

2.4L Engines
Exhaust Sensor
  1. Remove the engine oil fill cap.
  2.  
  3. Grasp the intake manifold cover by the lower right inboard corner and pull up to disengage the cover from the stud.
  4.  
  5. Grasp the intake manifold cover by the upper left corner and pull up to disengage the cover from the stud.
  6.  
  7. Remove the intake manifold cover.

    Click image to see an enlarged view

    Fig. Location of the Camshaft Position (CMP) sensor electrical connectors-2.4L engine

  8.  
  9. Disconnect the exhaust camshaft position (CMP) sensor electrical connector (1).
  10.  
  11. Remove the CMP sensor bolt.
  12.  
  13. Remove the CMP sensor.
  14.  

To install:


NOTE
Inspect the CMP sensor for damage, replace as necessary.

  1. Lubricate the CMP sensor O-ring seal with clean engine oil.
  2.  
  3. Install the CMP sensor.
  4.  
  5. Install the CMP sensor bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  6.  
  7. Connect the exhaust CMP sensor electrical connector (1).
  8.  
  9. Place the intake manifold cover onto the engine over the studs.
  10.  
  11. Push down on the intake manifold cover directly over the lower right stud in order to engage the cover to the stud.
  12.  
  13. Push down on the intake manifold cover directly over the upper left stud in order to engage the cover to the stud.
  14.  
  15. Install the engine oil fill cap.
  16.  

Intake Sensor
  1. Remove the engine oil fill cap.
  2.  
  3. Grasp the intake manifold cover by the lower right inboard corner and pull up to disengage the cover from the stud.
  4.  
  5. Grasp the intake manifold cover by the upper left corner and pull up to disengage the cover from the stud.
  6.  
  7. Remove the intake manifold cover.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) Sensor location for intake-2.2L & 2.4L engine



    Click image to see an enlarged view

    Fig. Location of the Camshaft Position (CMP) sensor electrical connectors-2.4L engine

  8.  
  9. Disconnect the intake camshaft position (CMP) sensor electrical connector (2).
  10.  
  11. Remove the CMP sensor bolt.
  12.  
  13. Remove the CMP sensor.
  14.  

To install:


NOTE
Inspect the CMP sensor for damage, replace as necessary.

  1. Lubricate the CMP sensor O-ring seal with clean engine oil.
  2.  
  3. Install the CMP sensor.
  4.  
  5. Install the CMP sensor bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  6.  
  7. Connect the intake CMP sensor electrical connector.
  8.  
  9. Place the intake manifold cover onto the engine over the studs.
  10.  
  11. Push down on the intake manifold cover directly over the lower right stud in order to engage the cover to the stud.
  12.  
  13. Push down on the intake manifold cover directly over the upper left stud in order to engage the cover to the stud.
  14.  
  15. Install the engine oil fill cap.
  16.  

Testing





Click image to see an enlarged view

Fig. CMP sensor connector end view-2.0L & 2.2L engines



Click image to see an enlarged view

Fig. CMP sensor connector end view for intake & exhaust-2.4L 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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