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Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK OPERATION OF SPEEDOMETER 
    1. Drive the vehicle and check if the function of the speedometer in the combination meter is normal.

      OK: 

      Actual vehicle speed and the speed indicated on the speedometer are the same. 

      HINT:

      The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

    NG: GO TO  COMBINATION METER SYSTEM 

    OK: Go to Next Step 

  2. INSPECT NAVIGATION ECU 
    1. Disconnect the navigation ECU connector N3.
      Fig 1: Identifying Navigation ECU Connector Terminals
      G05270956Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure voltage.
      1. Jack up either one of the drive wheels.
      2. Move the shift lever to the neutral position.
      3. Turn the ignition switch to the ON position.
      4. Measure the voltage between terminal SPD of the wire harness connector and body ground when the drive wheels are turned slowly.
        Fig 2: Identifying SPD Voltage Graph
        G04967013Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        OK: 

        Voltage pulses as shown below in the illustration: 

    OK: REPLACE NAVIGATION ECU 

    NG: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (COMBINATION METER - NAVIGATION ECU) 
    1. Disconnect the navigation ECU connector N3 and combination meter connector C8.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION REFERENCE TABLE

      Tester connection Condition Specified condition
      SPD - C8-6 Ignition switch off Below 1 Ω
      Fig 3: Identifying Navigation ECU & Combination Meter Connector Terminals
      G05270958Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  4. CHECK HARNESS AND CONNECTOR (NAVIGATION ECU - BODY GROUND) 
    1. Disconnect the navigation ECU connector N3.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION REFERENCE TABLE

      Tester connection Condition Specified condition
      SPD - Body ground Ignition switch off 10 kΩ or higher
      Fig 4: Identifying Navigation ECU Connector Terminals
      G05270959Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      If the resistance between terminal SPD and body ground is less than 10 kΩ, there may be a short in a wire harness, connector, or ECU.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU 

    OK: REPLACE COMBINATION METER 

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