2007 Jeep Compass

Knock Sensor

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Operation



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

The Knock Sensor (KS) is a piezo-electric (pressure-sensitive) electronic device that enables the Powertrain Control Module (PCM) 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



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

The knock sensor is bolted to the engine block in front of the starter, under the intake manifold.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the bolt holding the Knock Sensor (KS)
  6.  
  7. Remove the KS with the electrical connector attached.
  8.  
  9. Disconnect the electrical connector from the KS.
  10.  
  11. Remove the KS.

    Click image to see an enlarged view

    Fig. Knock Sensor (KS) location-2.0L and 2.4L engines

  12.  

To install:

  1. Attach the electrical connector to the KS.
  2.  
  3. Install the KS into the engine block. Tighten the bolt to 16 ft. lbs. (22 Nm).
    WARNING
    Over or under-tightening affects the knock sensor performance, possibly causing improper spark control.

  4.  
  5. Connect the negative battery cable.
  6.  

Testing



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009


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

Knock Sensor (KS) Strategy

Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

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 (See Figure 1). 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:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
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