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Home >> Lexus >> 2023 >> LX 600 Base >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Diagnostic Codes & Symptom Tests >> Meter / Gauge System >> Speed Signal Circuit [12/2021 - ] >> Procedure

Speed Signal Circuit [12/2021 - ]: Procedure

  1. CHECK DTC (SMART ACCESS SYSTEM WITH PUSH-BUTTON START) 
    1. Check if smart access system with push-button start DTCs are output.

      Body Electrical > Power Source Control > Trouble Codes 

      Result

      Proceed to 
      OK
      NG

    Result: 

    NG 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2021 - ] 

    Result: 

    OK 

    See step  2

  2. CHECK ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    GTY1058847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Combination Meter Assembly)
    1. Disconnect the combination meter assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I6-35 (+S) - Body ground Ignition switch ON 11 to 14 V

      HINT: 

      If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.

      Result

      Proceed to 
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  3

  3. CHECK COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I39-28 (SPDO) - Body ground Ignition switch ON 11 to 14 V
      GTY1059601Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Certification ECU (Smart Key ECU Assembly))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    GTY1067983Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component with harness connected
    (Combination Meter Assembly)
    *b Waveform
    1. Check the input waveform.
      1. Remove the combination meter assembly with the connector(s) still connected.

        Refer to REMOVAL [12/2021 - ]

      2. Connect an oscilloscope to terminal I6-18 (SI) and body ground.
      3. Turn the ignition switch to ON.
      4. Turn a wheel slowly.
      5. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Tester connection I6-18 (SI) - Body ground
        Tool setting 5 V/DIV., 20 ms./DIV.
        Condition Ignition switch ON, wheel being rotated

        OK

        The waveform is similar to that shown in the illustration.

        HINT: 

        When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Disconnect the I6 combination meter assembly connector.
    2. Disconnect the I39 certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I6-18 (SI) - I39-28 (SPDO) Always Below 1 Ω
      I6-18 (SI) or I39-28 (SPDO) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. *1: for 10 Speaker
    2. *2: for 25 Speaker
    1. Disconnect the combination meter assembly connector.
      GTY1060029Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    2. Disconnect the I196 multi-media module receiver assembly connector.
    3. Disconnect the S22*1 or S45*2 stereo component amplifier assembly connector.
    4. Disconnect the B70 ECM connector.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I6-35 (+S) - I196-8 (SPD) Always Below 1 Ω
      I6-35 (+S) - S22-17 (SPD)*1 Always Below 1 Ω
      I6-35 (+S) - S45-17 (SPD)*2 Always Below 1 Ω
      I6-35 (+S) - B70-33 (SPD) Always Below 1 Ω
      I6-35 (+S) or I196-8 (SPD) or S22-17 (SPD)*1 or S45-17 (SPD)*2 or B70-33 (SPD) - Body ground Always 10 kΩ or higher

      Result

      Proceed to 
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK MULTI-MEDIA MODULE RECEIVER ASSEMBLY 
    1. Disconnect the combination meter assembly connector.
      GTY1060029Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    2. Disconnect the I196 multi-media module receiver assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I6-35 (+S) - Body ground Ignition switch ON 11 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the multi-media module receiver assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MULTI-MEDIA MODULE RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    See step  8

  8. CHECK FOR STEREO COMPONENT AMPLIFIER ASSEMBLY 
    1. Disconnect the combination meter assembly connector.
      GTY1060029Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    2. Disconnect the S22*1 or S45*2 stereo component amplifier assembly connector.
      1. *1: for 10 Speaker
      2. *2: for 25 Speaker
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I6-35 (+S) - Body ground Ignition switch ON 11 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

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