METER / GAUGE SYSTEM Speed Signal Circuit

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.

Tech Tips

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

WIRING DIAGRAM

A017DEJE01

INSPECTION PROCEDURE

PROCEDURE


  1. 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

      Tech Tips

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


    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER - JUNCTION CONNECTOR) Click here

    OK

  2. 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

    NG

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

    OK

  3. 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.

        Tech Tips

        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.


    NG

    REPLACE SKID CONTROL ECU Click here

    OK

    REPLACE COMBINATION METER Click here

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - JUNCTION CONNECTOR)


    1. A017B07E01

      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) - E17-2 Always Below 1 Ω
      E1-9 (+S) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. 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.

      Tech Tips

      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. Disconnect the junction connectors.

        A017FZUE01

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

        Standard voltage
        Tester Connection Condition Specified Condition
        E17-3 (*2)- Body ground Ignition switch on (IG) 4.5 to 14 V
        E17-4 - Body ground Ignition switch on (IG) 4.5 to 14 V
        D46-9 (*1) - Body ground Ignition switch on (IG) 4.5 to 14 V
        D46-11 - 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

    B

    REPLACE JUNCTION CONNECTOR

    A

  6. 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
      D46-9 (*1) - Body ground Smart entry and start system A
      D46-11 - Body ground SFI system B
      E17-4 - Body ground Audio/visual system C
      E17-3 (*2) - Body ground Navigation system D

      *1: w/ Smart Entry and Start System

      *2: w/ Navigation System


    B

    CHECK HARNESS AND CONNECTOR (ECM CIRCUIT) Click here

    C

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT) Click here

    D

    CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER CIRCUIT) Click here

    A

  7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)


    1. A017FUDE01

      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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU

  8. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)


    1. A017CFEE10

      Disconnect the D32 connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D32-8 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here

  9. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT)


    1. A017BREE02

      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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE RADIO RECEIVER Click here

  10. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER CIRCUIT)


    1. A017DXAE03

      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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE NAVIGATION RECEIVER Click here

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


    1. A017EMAE02

      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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE COMBINATION METER Click here