Cobalt 2006-2008, G5 2007

Vehicle Speed Sensor

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Operation



Vehicle speed information is provided to the Engine Control Module (ECM) by the Vehicle Speed Sensor (VSS). The VSS is a permanent magnet generator that is mounted on the transaxle and produces a pulsing voltage when vehicle speed is over 3 mph (5 km/h). The AC voltage amplitude and frequency increases with vehicle speed. The ECM converts the pulsing voltage into mph (km/h). The ECM supplies the necessary signal to the instrument panel for speedometer, odometer operation, and to the cruise control module. If the ECM detects no vehicle speed for a specified length of time while other sensors indicate that the vehicle is moving, DTC-s are set.

Removal & Installation



Automatic Transaxle
4T45-E


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Fig. Location of the Vehicle Speed Sensor (VSS) on automatic transaxle 4T45-E


WARNING
Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle.
  4.  
  5. Remove the electrical connector at the Vehicle Speed Sensor (VSS).
  6.  
  7. Remove the retaining stud and the sensor. Pull straight out in order to avoid damage to the case.
  8.  

To install:

  1. Clean and dry the VSS.
    NOTE
    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2.  
  3. Install the VSS and the retaining bolt. Tighten the stud to 97 inch lbs. (12 Nm).
  4.  
  5. Install the electrical connector at the sensor.
  6.  
  7. Lower the vehicle.
  8.  
  9. Connect the negative battery cable. Tighten the terminal bolt to 11 ft. lbs. (15 Nm).
  10.  

Manual Transaxle
Getrag 5-Speed


Click image to see an enlarged view

Fig. Location of the Vehicle Speed Sensor (VSS) on manual transaxle-Getrag 5-speed

  1. Raise and safely support the vehicle.
  2.  
  3. Disconnect the Vehicle Speed Sensor (VSS) electrical connector.
  4.  
  5. Remove the retainer bolt.
  6.  
  7. Remove the retainer.
  8.  
  9. Pull up on the VSS in order to remove the VSS from the transaxle.
  10.  
  11. Remove the O-ring.
  12.  

To install:

  1. Lubricate a new O-ring with DEXRON III transmission fluid.
  2.  
  3. Install or connect the following:
    NOTE
    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.



    The new O-ring
     
    The VSS assembly
     
    The VSS retainer
     



    The VSS retainer bolt. Tighten the bolt to 96 inch lbs. (12 Nm)
     
    The VSS connector to the VSS
     

  4.  
  5. Lower the vehicle.
  6.  

MU3


Click image to see an enlarged view

Fig. Location of the Vehicle Speed Sensor (VSS) on manual transaxle-MU3

  1. Remove or disconnect the following:

    The left front wheel
     
    The Vehicle Speed Sensor (VSS) electrical connector (2)
     
    The retainer bolt
     
    The retainer
     
    The VSS
     
    Discard the O-ring
     

  2.  

To install:

  1. Lubricate a new O-ring with transmission fluid.
  2.  
  3. Install or connect the following:

    The new O-ring
     
    The VSS retainer
     
    The VSS assembly
     
    The VSS retainer bolt. Tighten the bolt to 80 inch lbs. (9 Nm)
     
    The VSS connector to the VSS
     
    The left front wheel. Tighten the lug nuts to 100 ft. lbs. (140 Nm)
     

  4.  

Testing



  1. Ensure the VSS is correctly tightened to the transmission housing.
  2.  
  3. Install a scan tool.
  4.  
  5. Turn ON the ignition, with the engine OFF.
    NOTE
    Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the ECM. Record the DTC Freeze Frame and Failure Records, then clear the DTC(s).

  6.  
  7. Raise and support the drive wheels.
  8.  
  9. Start and idle the engine.
  10.  
  11. Engage the transaxle in 2nd gear.
  12.  
  13. Select Vehicle Speed Sensor on the scan tool.
  14.  
  15. With the drive wheels rotating, the Vehicle Speed Sensor reading should increase when the wheel speed increases.
  16.  

 
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