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METER / GAUGE SYSTEM Speed Signal Circuit

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DTC Code DTC Name
  Speed Signal Circuit
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DESCRIPTION

The meter CPU receives vehicle speed signals from this circuit. The vehicle speed sensor detects the voltage that varies according to the vehicle speed. The skid control ECU supplies power to the vehicle speed sensor. The skid control ECU detects vehicle speed signals based on the pulses of the voltage. The skid control ECU transmits vehicle speed signals as pulses to the meter CPU. A voltage of 12 V is output from the combination meter assembly and then input to the skid control ECU. The signal is changed to a pulse signal at the transistor in the combination meter assembly.

A voltage of 12 V or 5 V is output from each ECU or relay and then input to the combination meter assembly.

Each ECU controls the respective system based on the pulse signal.

Tip:

This circuit is used for another system, and is not used for speedometer operation.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

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PROCEDURE


  1. Click here

    INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A017B5ME03

      Disconnect the E1 connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Condition Specified Condition
      E1-9 (+S) - Body ground Ignition switch on (IG) 4.5 to 14 V
      Tip:

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


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    INSPECT COMBINATION METER (OUTPUT VOLTAGE)


    1. Reconnect the E1 connector.

    2. A017G7GE01

      Disconnect the A24 connector.

    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Condition Specified Condition
      A24-11 (SP1) - Body ground Ignition switch on (IG) 11 to 14 V

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    INSPECT SKID CONTROL ECU (INPUT WAVEFORM)


    1. A017G2RE02

      Check the input waveform.


      1. Reconnect the A24 connector.

      2. Remove the combination meter assembly with the connector(s) still connected.

      3. Connect an oscilloscope to terminal E1-29 (SI) and body ground.

      4. Ignition switch on (IG).

      5. Turn the wheel slowly.

      6. 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 Driving at approx. 20 km/h (12 mph)
        OK
        The waveform is displayed as shown in the illustration.
        Tip:

        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.


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    CHECK HARNESS AND CONNECTOR (COMBINATION METER - JUNCTION CONNECTOR)


    1. Disconnect the junction connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      E1-9 (+S) - E17-6 Always Below 1 Ω
      E1-9 (+S) - Body ground Always 10 kΩ or higher

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    CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)


    1. Inspect for a short in the circuit that is connected to the junction connector shown in the wiring diagram.

      Tip:

      If voltage is not present, the circuit (ECU) is possibly malfunctioning. This is the circuit that will be diagnosed by following the A step that follows.


      1. A017FZUE01

        Disconnect the junction connectors.

      2. Measure the voltage according to the value(s) in the table below.

        Standard voltage
        Tester Connection Condition Specified Condition
        E17-7 (*2)- Body ground Ignition switch on (IG) 4.5 to 14 V
        E17-7 - Body ground Ignition switch on (IG) 4.5 to 14 V
        D46-5 (*1) - Body ground Ignition switch on (IG) 4.5 to 14 V
        D46-7 - Body ground Ignition switch on (IG) 4.5 to 14 V

        *1: w/ Smart Entry and Start System

        *2: w/ Navigation System

        Result
        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all the circuits. B

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    SYSTEM CHECK


    1. Select the circuit in which is not present voltage in step 5.

      Result
      Tester Connection System that uses the circuit Proceed to
      D46-5 (*1) - Body ground Smart entry and start system A
      D46-7 - Body ground SFI system B
      E17-7 (*3) - Body ground Audio/visual system C
      E17-7 (*2) - Body ground Navigation system D

      *1: w/ Smart Entry and Start System

      *2: w/ Navigation System

      *3: w/ Radio Receiver


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    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)


    1. Disconnect the D8 (*) connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      D8-9 (SPD) (*) - Body ground Always 10 kΩ or higher

      *: w/ Smart Entry and Start System


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    CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)


    1. Disconnect the D56 connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      D56-18 (SPD) - Body ground Always 10 kΩ or higher

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    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT)


    1. Disconnect the E2 connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      E2-3 (SPD) - Body ground Always 10 kΩ or higher

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    CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER CIRCUIT)


    1. Disconnect the E4 (*) connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      E4-3 (SPD) (*) - Body ground Always 10 kΩ or higher

      *: w/ Navigation System


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    CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU)


    1. Disconnect the E1 connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      A24-11 (SP1) - E1-29 (SI) Always Below 1 Ω
      A24-11 (SP1) - Body ground Always 10 kΩ or higher

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    REPLACE COMBINATION METERClick here

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    REPLACE SKID CONTROL ECUClick here

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPLACE MAIN BODY ECU

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    REPLACE ECMClick here

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    REPLACE RADIO RECEIVERClick here

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    REPLACE NAVIGATION RECEIVERClick here

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    REPLACE JUNCTION CONNECTOR