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 brake actuator assembly (skid control ECU) which uses this information to create the vehicle speed signal*a. The vehicle speed signal consists of pulses sent to the combination meter assembly from the brake actuator assembly (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 brake actuator assembly (skid control ECU). The pulse signal is created by switching the transistor in the brake actuator assembly (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 brake actuator assembly (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 this 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

B00683WE03

CAUTION / NOTICE / HINT

Note

Before replacing the ECM or certification ECU (smart key ECU assembly), refer to Service Bulletin.

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. B0066YIC22
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the O3 combination meter assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine 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.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the O3 combination meter assembly connector.

    2. B0067M3C07
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

      Disconnect the A86 brake actuator assembly (skid control ECU) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A86-14 (SP1) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  3. INSPECT BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) (INPUT WAVEFORM)


    1. B0066TXC21
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A86 brake actuator assembly (skid control ECU) connector.

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

      3. Connect an oscilloscope to terminal O3-20 (SI) and body ground.

      4. Turn the engine switch on (IG).

      5. Turn a 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 Engine switch on (IG), wheel being rotated
        OK
        The waveform is similar to that 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
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) for RHD: Click here

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


    1. Disconnect the O3 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O3-20 (SI) - A86-14 (SP1) Always Below 1 Ω
      O3-20 (SI) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU)


    1. Disconnect the A78 ECM connector.

    2. Disconnect the O6 certification ECU (smart key ECU assembly) connector.

    3. Disconnect the O65 DCM (Telematics Transceiver) connector*1.

    4. Disconnect the O146 radio receiver assembly connector.

    5. Disconnect the O150 navigation ECU connector*2.

    6. Disconnect the T20*2 or T51*3 stereo component amplifier assembly connector.

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


      • *1: w/ Telematics Transceiver except G-BOOK

      • *2: for 10.3 Inch Multi-display Assembly

      • *3: for 7 Inch Multi-display Assembly (for 10 Speakers)

      Standard Resistance
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT ECM (SHORT CIRCUIT IN ECM)


    1. Connect the O6 certification ECU (smart key ECU assembly) connector.

    2. Connect the O65 DCM (Telematics Transceiver) connector*1.

    3. Connect the O146 radio receiver assembly connector.

    4. Connect the O150 navigation ECU connector*2.

    5. Connect the T20*2 or T51*3 stereo component amplifier assembly connector.

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


      • *1: w/ Telematics Transceiver except G-BOOK

      • *2: for 10.3 Inch Multi-display Assembly

      • *3: for 7 Inch Multi-display Assembly (for 10 Speakers)

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the ECM.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  7. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY)


    1. Connect the A78 ECM connector.

    2. Disconnect the O146 radio receiver assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result
      Result
      OK
      NG

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    NG

  8. CONFIRM MODEL

    Result
    Result Proceed to
    w/ Telematics Transceiver except G-BOOK A
    w/ Telematics Transceiver for G-BOOK B
    w/o Telematics Transceiver

    B

    CONFIRM MODEL Click here

    A

  9. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN DCM (TELEMATICS TRANSCEIVER))


    1. Connect the O146 radio receiver assembly connector.

    2. Disconnect the O65 DCM (Telematics Transceiver) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the DCM (Telematics Transceiver).

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

  10. CONFIRM MODEL

    Result
    Result Proceed to
    for 10.3 Inch Multi-display Assembly A
    for 7 Inch Multi-display Assembly (for 10 Speakers) B
    for 7 Inch Multi-display Assembly (except 10 Speakers) C

    B

    INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) Click here

    C

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

  11. INSPECT NAVIGATION ECU (SHORT CIRCUIT IN NAVIGATION ECU)


    1. Connect the O65 DCM (Telematics Transceiver) connector.*1

    2. Connect the O146 radio receiver assembly connector.*2, *3

    3. Disconnect the O150 navigation ECU connector.

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


      • *1: w/ Telematics Transceiver except G-BOOK

      • *2: w/ Telematics Transceiver for G-BOOK

      • *3: w/o Telematics Transceiver

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NAVIGATION ECU Click here

    NG

  12. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)


    1. Connect the O150 navigation ECU connector.

    2. Disconnect the T20 stereo component amplifier assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  13. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)


    1. Connect the O65 DCM (Telematics Transceiver) connector.*1

    2. Connect the O146 radio receiver assembly connector.*2, *3

    3. Disconnect the T51 stereo component amplifier assembly connector.

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


      • *1: w/ Telematics Transceiver except G-BOOK

      • *2: w/ Telematics Transceiver for G-BOOK

      • *3: w/o Telematics Transceiver

      Standard Voltage
      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)