METER / GAUGE SYSTEM Speed Signal Circuit

DESCRIPTION

The combination meter assembly receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the skid control ECU which uses this information to create the vehicle speed sensor signal*a. The vehicle speed sensor signal consists of pulses sent to the combination meter assembly from the skid control ECU. To create this signal, 12 V is output from IG2 which is behind a resistor in the combination meter assembly. This voltage is sent to the skid control ECU. The pulse signal is created by switching the transistor in the skid control ECU on and off, making the voltage on the wire drop to 0 V. A similar system is used for the output of this signal from the combination meter assembly via terminal +S. A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal. The transistor in the combination meter assembly is controlled by the signal from the skid control ECU. When this transistor is turned on, this transistor makes the voltage supplied by the various ECUs (via their respective internal resistors) drop to 0 V. Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on the pulse signal.


Tech Tips

This circuit is used for the systems connected to terminal +S. This signal is not used for combination meter assembly operation. Combination meter assembly components such as the speedometer operate using data received via CAN communication.

WIRING DIAGRAM

A003ZQ1E01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A003YSIE89
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the H19 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H19-40 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

      Tech Tips

      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.


    NG

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

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the H19 connector.

    2. A003VYDE56
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

      Disconnect the A61 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A61-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V

    NG

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

    OK

  3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)


    1. A003VBRE64
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A61 connector.

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

      3. Connect an oscilloscope to terminal H19-39 (SI) and body ground.

      4. Turn the power 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 Wheel being rotated
        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.

        Result
        Result Proceed to
        OK A
        NG (for LHD) B
        NG (for RHD) C

    B

    REPLACE SKID CONTROL ECU Click here

    C

    REPLACE SKID CONTROL ECU Click here

    A

    REPLACE COMBINATION METER ASSEMBLY Click here

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


    1. Disconnect the H19 and A61 connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A61-11 (SP1) - H19-39 (SI) Always Below 1 Ω
      A61-11 (SP1) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - 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
      H19-40 (+S) - H117-59 Always Below 1 Ω
      H19-40 (+S) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)


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

      Tech Tips

      If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.


      1. Disconnect the 3B connector.

        A003Z88E02

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        H117-29 - Body ground Power switch on (IG) 4.5 to 14 V
        H117-19 - Body ground Power switch on (IG) 4.5 to 14 V
        H117-89 - Body ground Power switch on (IG) 4.5 to 14 V
        H117-58 - Body ground Power switch on (IG) 4.5 to 14 V
        H117-79 - Body ground Power switch on (IG) 4.5 to 14 V
        H117-99 - Body ground Power switch on (IG) 4.5 to 14 V
        Text in Illustration
        *a

        Front view of wire harness connector

        (to Junction Connector)
        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

  7. SYSTEM CHECK


    1. Select the circuit for which voltage was not present in step 6.

      Result
      Tester Connection System that Uses the Circuit Proceed to
      H117-29 - Body ground Hybrid Control System A
      H117-19 - Body ground Wiper and Washer System*1 B
      H117-58 - Body ground Lighting System*2 C
      H117-89 - Body ground Audio/Visual System D
      H117-99 - Body ground Audio/Visual System D
      H117-99 - Body ground Navigation System*3 or *4 D

      • *1: w/ Auto Wiper System

      • *2: w/ Automatic Type Headlight Beam Level Control

      • *3: w/ Navigation System (for DVD)

      • *4: w/ Navigation System (for HDD)


    B

    CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT) Click here

    C

    CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT) Click here

    D

    SYSTEM CHECK Click here

    A

  8. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)


    1. Disconnect the H3 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H3-14 (SPDI) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

  9. CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT)


    1. Disconnect the H75 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H75-19 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY Click here

  10. CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT)


    1. Disconnect the A46 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A46-16 (SPDR) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

  11. SYSTEM CHECK


    1. Select the circuit for which voltage was not present in step 6.

      Result
      Tester Connection System that Uses the Circuit Proceed to
      H117-89 - Body ground Audio/Visual System A
      H117-99 - Body ground Audio/Visual System B
      H117-99 - Body ground Navigation System*1 or *2 B

      • *1: w/ Navigation System (for DVD)

      • *2: w/ Navigation System (for HDD)


    B

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT) Click here

    A

  12. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)


    1. Disconnect the H56*1 or H55*2 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H56-2 (SPD)*1 - Body ground Always 10 kΩ or higher
      H55-11 (SPD)*2 - Body ground Always 10 kΩ or higher

      • *1: w/ Navigation System

      • *2: w/o Navigation System


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

  13. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT)


    1. Disconnect the H47*1, H52*2, or H60*3 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H47-17 (SPD)*1 - Body ground Always 10 kΩ or higher
      H52-3 (SPD)*2 - Body ground Always 10 kΩ or higher
      H60-18 (SPD)*3 - Body ground Always 10 kΩ or higher

      • *1: w/o Navigation System, w/ Built-in Type Amplifier

      • *2: w/o Navigation System, w/ Separate Type Amplifier

      • *3: w/ Navigation System

      Result
      Result Proceed to
      OK (w/o Navigation System) A
      OK (w/ Navigation System (for HDD)) B
      OK (w/ Navigation System (for DVD)) C
      NG D

    B

    REPLACE NAVIGATION COMPUTER SUB-ASSEMBLY Click here

    C

    REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Click here

    D

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE RADIO RECEIVER ASSEMBLY Click here