Altima 2007-2009

Knock Sensor

Print

Location



2.5L Engine

Specific to:

Nissan Altima 2007-2008

Refer to the accompanying illustration for sensor location.

Click image to see an enlarged view

Fig. The Knock Sensor (KS) is on the front of the engine block near the oil cooler-2.5L engine

Specific to:

Nissan Altima 2009-2010

The knock sensor is attached to the cylinder block.

Click image to see an enlarged view

Fig. Knock sensor (14) location near engine oil cooler (15)-2.5L engine

3.5L Engine

Specific to:

Nissan Altima 2007-2008

Refer to the accompanying illustration for sensor location.

Click image to see an enlarged view

Fig. There are two Knock Sensors (KS) in the valley between the cylinder heads-3.5L engine

Specific to:

Nissan Altima 2009-2010



Click image to see an enlarged view

Fig. Knock sensor (bank 2) (1) and knock sensor (bank 1) (2)-3.5L engine

Operation



Specific to:

Nissan Altima 2007-2008

The Knock Sensor(s) (KS) attached to the cylinder block senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as extremely rapid pressure changes (vibration). This pressure change is converted into a voltage signal and sent to the ECM.

Specific to:

Nissan Altima 2009-2010

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



Specific to:

Nissan Altima 2007-2008

  1. Remove the bolt to remove the sensor from the engine block.
  2.  
  3. Installation is the reverse of the removal procedure. During installation, do not over tighten the bolt or the sensor will not function properly.

    Click image to see an enlarged view

    Fig. The Knock Sensor (KS) is on the front of the engine block near the oil cooler-2.5L engine



    Click image to see an enlarged view

    Fig. There are two Knock Sensors (KS) in the valley between the cylinder heads-3.5L engine

  4.  

Specific to:

Nissan Altima 2009-2010


NOTE
The manufacturer does not provide a specific Removal and Installation procedure for this component. Refer to the graphic(s) when servicing this component.

Testing



Specific to:

Nissan Altima 2007-2008

  1. Turn ignition switch OFF and wait at least 10 seconds before going to the next step.
  2.  
  3. Confirm that battery voltage is more than 11V with the engine at idle.
  4.  
  5. Start engine and warm it up to normal operating temperature.
  6.  
  7. Let it idle for 2 minutes and check for 1st trip DTC. If there is no code, the sensor is working properly or the problem is intermittent. Check the sensor power and ground circuits.
    WARNING
    Connect the voltmeter ground probe to engine or chassis ground. Do not test circuits with the meter connected to the battery or the ECM may be damaged.

  8.  
  9. Disconnect knock sensor harness connector and ECM harness connector.
  10.  
  11. Check the continuity between knock sensor harness connector and ECM harness connector. Also check for short circuits to power or ground.
  12.  
  13. Check resistance across the sensor connector terminals. Resistance should be approximately 532,000-588,000 ohms at room temperature.
  14.  

Specific to:

Nissan Altima 2009-2010


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

Knock Sensor Strategy

Specific to:

Nissan Altima 2009-2010

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:

Nissan Altima 2009-2010



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
label.common.footer.alt.autozoneLogo