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Home >> Toyota >> 2021 >> Mirai XLE >> Repair and Diagnosis >> Electrical >> Gauges >> Meter / Gauge System - Diagnostic Codes (3 Of 3) & Symptom Tests >> Meter / Gauge System >> Speed Signal Circuit [12/2023 - ] >> Procedure

Speed Signal Circuit [12/2023 - ]: Procedure

  1. CHECK VEHICLE TYPE 
    1. Check vehicle condition.

      Result

      Result  Proceed to 
      w/ Front LiDAR Sensor A
      w/o Front LiDAR Sensor B

    Result: 

    B 

    See step  9

    Result: 

    A 

    See step  2

  2. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    1. Disconnect the D44 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
      D44-8 (+S) - Body ground Ignition switch ON 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  6

    Result: 

    OK 

    See step  3

  3. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Disconnect the A6 brake actuator assembly (No. 2 skid control ECU).
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A6-18 (SP1) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    1. Check the input waveform.
      GTY982799Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Combination Meter Assembly)
      *b Waveform
      1. Remove the combination meter assembly with the connector(s) still connected.
      2. Turn the ignition switch to ON.
      3. Turn a wheel slowly.
      4. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Tester connection D44-25 (SI) - Body ground
        Tool setting 5 V/DIV., 20 ms./DIV.
        Vehicle 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 [12/2023 - ] 

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY (NO. 2 SKID CONTROL ECU). Refer to  REMOVAL [12/2023 - ] 

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NO. 2 SKID CONTROL ECU ASSEMBLY) 
    1. Disconnect the D44 combination meter assembly connector.
    2. Disconnect the A6 brake actuator assembly (No. 2 skid control ECU) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D44-25 (SI) - A6-18 (SP1) Always Below 1 Ω
      D44-25 (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 [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU) 
    1. Disconnect the D44 combination meter assembly connector.
    2. Disconnect the D86 certification ECU (smart key ECU assembly) connector.
    3. Disconnect the G54 stereo component amplifier assembly connector.
    4. Disconnect the D61 radio and display receiver assembly connector.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D44-8 (+S) - Other terminals and 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. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) 
    1. Disconnect the D44 combination meter assembly connector.
    2. Disconnect the G54 stereo component amplifier assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D44-8 (+S) - Body ground Ignition switch ON 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 [12/2022 - ] 

    Result: 

    NG 

    See step  8

  8. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO AND DISPLAY RECEIVER ASSEMBLY) 
    1. Disconnect the D44 combination meter assembly connector.
    2. Disconnect the D61 radio and display receiver assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D44-8 (+S) - Body ground Ignition switch ON 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 AND DISPLAY RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2023 - ] 

  9. CHECK DTC (SMART KEY SYSTEM) 
    1. Check if smart key systemsmart key system DTCs are output.

      Body Electrical > Power Source Control > Trouble Codes 

      Result

      Proceed to 
      OK
      NG

    Result: 

    NG 

    GO TO SMART KEY SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2023 - ] 

    Result: 

    OK 

    See step  10

  10. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    1. Disconnect the D199 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
      D199-8 (+S) - Body ground Ignition switch ON 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  13

    Result: 

    OK 

    See step  11

  11. INSPECT COMBINATION METER ASSEMBLY 

    HINT: 

    This procedure is performed to check the diode inside the combination meter assembly.

    1. Remove the combination meter assembly.

      Refer to REMOVAL [12/2023 - ]

    2. Measure the internal resistance of the combination meter assembly.

      Standard Resistance

      Tester Connection Tester Connection Condition Measured Value
      D199-6 (IG+) - D199-25 (SI)
      • Positive (+) tester probe → D199-6 (IG+)
      • Negative (-) tester probe → D199-25 (SI)
      		 Always A
      D199-6 (IG+) - D199-25 (SI)
      • Positive (+) tester probe → D199-25 (SI)
      • Negative (-) tester probe → D199-6 (IG+)
      		 Always B

      OK

      There is a large difference between the measured value (A) and the measured value (B).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU ASSEMBLY) 
    1. Disconnect the D199 combination meter assembly connector.
    2. Disconnect the D203 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
      D199-25 (SI) - D203-28 (SPDO) Always Below 1 Ω
      D199-25 (SI) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU) 
    1. Disconnect the D199 combination meter assembly connector.
    2. Disconnect the G164 stereo component amplifier assembly connector.
    3. Disconnect the D61 radio and display receiver assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D199-8 (+S) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) 
    1. Disconnect the D199 combination meter assembly connector.
    2. Disconnect the G164 stereo component amplifier assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D199-8 (+S) - Body ground Ignition switch ON 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 [12/2022 - ] 

    Result: 

    NG 

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

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