H3 2006

Knock Sensor

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Operation



Specific to:

Hummer H3 2006-2010

The Knock Sensor (KS) is a piezo-electric (pressure-sensitive) electronic device that enables the Powertrain Control Module (PSM) to control the ignition timing for optimum performance, and to protect the engine from potentially damaging levels of detonation. The PCM uses the KS system to test for abnormal engine noise that may indicate detonation, which is also known as spark knock.

Removal & Installation



3.5L & 3.7L Engine
  1. Raise and support the vehicle only high enough to access the knock sensor through the wheelhouse.
  2.  
  3. Remove the left wheel and tire.
  4.  
  5. Remove the left wheelhouse liner.
  6.  
  7. Disconnect the engine wiring harness electrical connector from the knock sensor.

    Click image to see an enlarged view

    Fig. Disconnect the engine wiring harness electrical connector (3) from the knock sensor (1); engine wiring harness

  8.  
  9. Remove the knock sensor bolt.
  10.  
  11. Remove the knock sensor.
  12.  

To install:

  1. Install the knock sensor and the bolt to the engine block, positioning the electrical terminals rearward. Tighten the bolt to 18 ft. lbs. (25 Nm).
  2.  
  3. Connect the engine wiring harness electrical connector to the knock sensor.
  4.  
  5. Install the left wheelhouse liner.
  6.  
  7. Install the wheel and tire.
  8.  
  9. Lower the vehicle.
  10.  

5.3L Engine
Knock Sensor 1

Specific to:

Hummer H3 2006-2010

  1. Raise and suitably support the vehicle.
  2.  
  3. Disconnect the engine wiring harness electrical connector from the knock sensor.

    Click image to see an enlarged view

    Fig. Disconnect the engine wiring harness electrical connector from the knock sensor

  4.  
  5. Remove the knock sensor bolt and sensor.

    Click image to see an enlarged view

    Fig. Remove the knock sensor bolt (739) and sensor (718)

  6.  

To install:

  1. Position the knock sensor to the engine block and install the bolt. Tighten the bolt to 15 ft. lbs. (20 Nm).
  2.  
  3. Connect the engine wiring harness electrical connector to the knock sensor.
  4.  
  5. Lower the vehicle.
  6.  

Knock Sensor 2

Specific to:

Hummer H3 2006-2010

  1. Raise and suitably support the vehicle.
  2.  
  3. Disconnect the engine wiring harness electrical connector from the knock sensor.

    Click image to see an enlarged view

    Fig. Disconnect the engine wiring harness electrical connector from the knock sensor

  4.  
  5. Remove the knock sensor bolt and sensor.

    Click image to see an enlarged view

    Fig. Remove the knock sensor bolt (739) and sensor (718)

  6.  

To install:

  1. Position the knock sensor to the engine block and install the bolt. Tighten the bolt to 15 ft. lbs. (20 Nm).
  2.  
  3. Connect the engine wiring harness electrical connector to the knock sensor.
  4.  
  5. Lower the vehicle.
  6.  

Testing



Specific to:

Hummer H3 2006-2010


NOTE
Refer to the Electrical Wiring Diagram for component and connector locations, connector views, and circuit-specific information.

Knock Sensor Strategy

Specific to:

Hummer H3 2006-2010

The Knock Sensor (KS) system uses one or two broadband one-wire sensors. The Knock Sensor generates an AC voltage signal of varying amplitude and frequency based on the engine vibration. The amplitude and frequency are dependent upon the level of knock that the KS detects. The control module receives the KS signal through a signal circuit, and the KS ground is supplied by the engine block through the sensor housing.

Click image to see an enlarged view

Fig. Active Knock Sensor (KS) Pattern

Related Diagnostic Trouble Codes

Specific to:

Hummer H3 2006-2010



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
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