LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2021 >> LC 500h >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Diagnostic Codes, Symptom & Circuit Tests >> Meter / Gauge System >> Speed Signal Circuit [06/2019 - 05/2023] >> Procedure

Speed Signal Circuit [06/2019 - 05/2023]: Procedure

  1. CHECK ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    1. Disconnect the combination meter assembly connector.
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P25-19 (+S) - Body ground Power switch on (IG) 4.5 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  5

    Result: 

    OK 

    See step  2

  2. CHECK COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Disconnect the P25 combination meter assembly connector.
    2. Disconnect the skid control ECU assembly connector.
      GTY787716Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU Assembly)
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A9-22 (SP1) - Body ground Power switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  4

    Result: 

    OK 

    See step  3

  3. CHECK COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    1. Check the input waveform.
      GTY783479Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Combination Meter Assembly)
      1. Remove the combination meter assembly with the connector(s) still connected.
      2. Connect an oscilloscope to terminal P25-20 (SI) and body ground.
      3. Turn the power switch on (IG).
      4. Turn a wheel slowly.
      5. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Tool setting 5 V/DIV., 20 ms./DIV.
        Vehicle condition Power switch on (IG) 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 [01/2017 - ] 

    Result: 

    NG 

    REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [01/2017 - 05/2023] 

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU ASSEMBLY) 
    1. Disconnect the P25 combination meter assembly connector.
    2. Disconnect the A9 skid control ECU assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P25-20 (SI) - A9-22 (SP1) Always Below 1 Ω
      P25-20 (SI) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [01/2017 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU) 
    1. Disconnect the P66 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the X49 stereo component amplifier assembly connector.
    3. Disconnect the P47 navigation ECU connector.
    4. Disconnect the P43 radio receiver assembly connector.
    5. Disconnect the Z2 map light sub-assembly connector.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P25-19 (+S) - Other terminals and body ground Always 10 kΩ or higher
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER) 
    1. Disconnect the combination meter assembly connector.
    2. Disconnect the P43 radio receiver assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P25-19 (+S) - Other terminals and body ground Power switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    NG 

    See step  7

  7. CHECK STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER) 
    1. Disconnect the combination meter assembly connector.
    2. Disconnect the X49 stereo component amplifier assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P25-19 (+S) - Other terminals and body ground Power switch on (IG) 4.5 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 [01/2017 - 05/2023] 

    Result: 

    NG 

    See step  8

  8. CHECK NAVIGATION ECU (SHORT CIRCUIT IN NAVIGATION ECU) 
    1. Disconnect the combination meter assembly connector.
    2. Disconnect the P47 navigation ECU connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P25-19 (+S) - Other terminals and body ground Power switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the navigation ECU.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NAVIGATION ECU. Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    NG 

    See step  9

  9. CHECK MAP LIGHT SUB-ASSEMBLY (SHORT CIRCUIT IN NAVIGATION ECU) 
    1. Disconnect the combination meter assembly connector.
    2. Disconnect the Z2 map light sub-assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY827461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P25-19 (+S) - Other terminals and body ground Power switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the map light sub-assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAP LIGHT SUB-ASSEMBLY. Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [01/2017 - 05/2023] 

scientia non olet · About LEMON Manuals