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Malfunction in Speedometer: Wiring Diagram

Fig 1: Malfunction In Speedometer - Wiring Diagram
G04022058Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER 
    1. Operate the intelligent tester according to the display and select the "Active Test".

      Combination meter 

      COMBINATION METER SPECIFICATION

      Item Test Details Diagnostic Note
      SPEED METER 0 / 40(24) / 80(48) / 120(72) / 160(96) / 200(120) / 240(149)km/h(mph) -

      OK : Needle indication is normal. 

    NG : REPLACE COMBINATION METER 

    OK : GO TO NEXT STEP 

  2. READ VALUE OF INTELLIGENT TESTER 
    1. Operate the intelligent tester according to the display and select the "Data List".

      Combination meter 

      COMBINATION METER SPECIFICATION

      Item Measurement Item / Range (Display) Normal Condition Diagnostic Note
      SPEED METER Vehicle speed / Min.: 0 km/h (0 mph), Max.: 255 km/h (158 mph) Almost same as actual vehicle speed (When driving) -

      OK : Vehicle speed displayed on the tester is almost the same as the actual vehicle speed. 

    NG : Go to step 3 

    OK : REPLACE COMBINATION METER 

  3. READ VALUE OF INTELLIGENT TESTER 
    1. Operate the intelligent tester according to the display and select the "Data List".

      Skid control ECU 

      SKID CONTROL ECU

      Item Measurement Item / Range (Display) Normal Condition Diagnostic Note
      FR WHEEL SPD Wheel speed sensor (FR) reading/ Min.: 0 km/h (0 mph), Max.: 326km/h (202 mph) Almost same as actual vehicle speed (When driving) -
      FL WHEEL SPD Wheel speed sensor (FL) reading/ Min.: 0 km/h (0 mph), Max.: 326km/h (202 mph) Almost same as actual vehicle speed (When driving) -
      RR WHEEL SPD Wheel speed sensor (RR) reading/ Min.: 0 km/h (0 mph), Max.: 326km/h (202 mph) Almost same as actual vehicle speed (When driving) -
      RL WHEEL SPD Wheel speed sensor (RL) reading/ Min.: 0 km/h (0 mph), Max.: 326km/h (202 mph) Almost same as actual vehicle speed (When driving) -

      OK : Vehicle speed displayed on the tester is almost the same as the actual vehicle speed. 

    NG : GO TO BRAKE CONTROL 

    OK : GO TO NEXT STEP 

  4. INSPECT COMBINATION METER 
    1. Check the input signal waveform.
      1. Remove the combination meter with the connector still connected.
      2. Connect the oscilloscope to the terminals K31-29 and body ground.
      3. Start the engine.
        Fig 2: Identifying K31 Connector Terminal 29
        G04022059Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Check the signal waveform of the connector.
        ITEM CONDITION CHART

        Item Condition
        Tool setting 5 V/DIV, 20 ms/DIV.
        Vehicle condition Driving at approx. 20 km/h (12 mph)

        OK : As shown in the illustration 

        HINT:

        As vehicle speed increases, the cycle of the signal waveform narrows.

    NG : Go to step 5 

    Fig 3: Identifying Waveform
    G04022060Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : REPLACE COMBINATION METER 

  5. CHECK HARNESS AND CONNECTOR (BETWEEN COMBINATION METER AND SKID CONTROL ECU) 
    1. 3UZ-FE
      1. Disconnect the K31 meter connector.
      2. Disconnect the A13 ECU connector.
      3. Measure the resistance of the wire harness side connectors.

        Standard resistance 

        STANDARD RESISTANCE SPECIFICATION

        Tester Connection Condition Specified Condition
        K31-29 - A13-7 Always Below 1 Ω
        K31-29 - Body ground Always 10 kΩ or higher
        Fig 4: Identifying K31 Meter Connector And A13 ECU Connector
        G04022061Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. 3GR-FSE
      1. Disconnect the K31 meter connectors.
      2. Disconnect the A44 ECU connectors.
      3. Measure the resistance of the wire harness side connectors.

        Standard resistance 

        STANDARD RESISTANCE SPECIFICATION

        Tester Connection Condition Specified Condition
        K31-29 - A44-12 Always Below 1 Ω
        K31-29 - Body ground Always 10 kΩ or higher

    NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

    Fig 5: Identifying K31 Meter Connectors And A44 ECU Connectors
    G04022062Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : GO TO NEXT STEP 

  6. CHECK SKID CONTROL ECU 
    1. 3UZ-FE
      1. Disconnect the A13 connector.
      2. Measure the voltage of the wire harness side connector.

        Standard voltage 

        STANDARD VOLTAGE SPECIFICATION

        Tester Connection Condition Specified Condition
        A13-7 - Body ground Engine switch on (IG) 10 to 14 V
        Fig 6: Identifying A13 Connector
        G04022063Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. 3GR-FSE
      1. Disconnect the A44 connector.
      2. Measure the voltage of the wire harness side connector.

        Standard Voltage 

        STANDARD VOLTAGE SPECIFICATION

        Tester Connection Condition Specified Condition
        A44-12 - Body ground Engine switch on (IG) 10 to 14 V

    OK : REPLACE COMBINATION METER 

    Fig 7: Identifying A44 Connector
    G04022064Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG : GO TO BRAKE CONTROL 

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