RX300 1999

Knock Sensor

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Operation



Specific to:

Lexus RX300 1999-2003

Lexus RX330 2004-2006

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:

Lexus RX300 1999-2003

At this time the manufacturer does not provide removal and installation procedures for this component. The following procedure is a guideline and may differ from the vehicle you are servicing.

  1. Before servicing the vehicle, refer to the Precautions Section.
    NOTE
    If working near and/or around the SRS system and components, be sure to disable the SRS system.

  2.  
  3. Disconnect the negative battery cable.
    NOTE
    When disconnecting the cable be sure that the ignition switch and headlight switches are off.


    NOTE
    When disconnecting the cable, certain systems will have to be initialized after reconnecting the cable. These systems are adaptive front lighting system, power window control system, power back door system, SRS system, audio system, sliding roof system and certain DTC codes. Be sure to write down any important information before disconnecting the cable. The Toyota scan tool, or equivalent, must be used. Follow the directions on the appropriate scan tool to complete initialization procedure.

  4.  
  5. Remove the necessary components in order to gain access to the sensor.
  6.  
  7. Remove the sensor from its mounting.
  8.  
  9. Discard the gasket, if equipped.

    Click image to see an enlarged view

    Fig. Knock sensor and related components (1 of 2)-RX300



    Click image to see an enlarged view

    Fig. Knock sensor and related components (2 of 2)-RX300

  10.  

To install:


NOTE
Be sure to use new fasteners, as required.

  1. Installation is the reverse of the removal procedure.
  2.  

Testing



Knock Sensor Strategy

Specific to:

Lexus RX300 1999-2003

Lexus RX330 2004-2006

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:

Lexus RX300 1999-2003

Lexus RX330 2004-2006



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
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