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 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

A0009JBE01

PROCEDURE


  1. INSPECT COMBINATION METER ASSEMBLY (INPUT VOLTAGE)


    1. A0007JXE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the H14 combination meter assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H14-19 (+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 H14 combination meter assembly connector.

    2. A0005SVE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Booster with Master Cylinder Assembly (Skid Control ECU))

      Disconnect the A24 brake booster with master cylinder 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
      A24-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU)) Click here

    OK

  3. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) (INPUT WAVEFORM)


    1. A0006O0E01
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A24 brake booster with master cylinder assembly (skid control ECU) connector.

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

      3. Connect an oscilloscope to terminal H14-20 (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 Power 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
        Result Proceed to
        OK A
        NG (for LHD) B
        NG (for RHD) C

    A

    REPLACE COMBINATION METER ASSEMBLY Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) Click here

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU))


    1. Disconnect the H14 combination meter assembly connector.

    2. Disconnect the A24 brake booster with master cylinder assembly (skid control ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H14-20 (SI) - A24-11 (SP1) Always Below 1 Ω
      H14-20 (SI) - Body ground Always 10 kΩ or higher

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the H115 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H14-19 (+S) - H115-21 Always Below 1 Ω
      H14-19 (+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 wire harness and connectors connected to the junction 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 H114 and H115 junction connectors.

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        H114-12 - Body ground Power switch on (IG) 4.5 to 14 V
        H114-13 - Body ground Power switch on (IG) 4.5 to 14 V
        H114-14 - Body ground Power switch on (IG) 4.5 to 14 V
        H114-15 - Body ground Power switch on (IG) 4.5 to 14 V
        H115-19 - Body ground Power switch on (IG) 4.5 to 14 V
        H115-21 - Body ground Power switch on (IG) 4.5 to 14 V
        Result
        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all of the circuits. B

    B

    REPLACE JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE)

    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
      H114-13 - Body ground Auto wiper system*1 A
      H114-14 - Body ground Smart entry and start system B
      H114-15 - Body ground Audio and visual system*2 or Navigation system*3 C
      H114-12 - Body ground Telematics system*4 D
      H115-19 - Body ground Vehicle proximity notification system*5
      H115-21 - Body ground Audio and visual system*2 or Navigation system*3

      • *1: w/ Auto Wiper System

      • *2: w/o Navigation System

      • *3: w/ Navigation System

      • *4: w/ Telematics Transceiver

      • *5: w/ Vehicle Proximity Notification System


    B

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) CIRCUIT) Click here

    C

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY CIRCUIT) Click here

    D

    SYSTEM CHECK Click here

    A

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


    1. Disconnect the H51 windshield wiper relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H51-24 (SPD) - Body ground Always 10 kΩ or higher

    OK

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) CIRCUIT)


    1. Disconnect the H194 certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H194-27 (SPD) - Body ground Always 10 kΩ or higher

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  10. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY CIRCUIT)


    1. Disconnect the H176*1 or H97*2 radio receiver assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H176-17 (SPD)*1 - Body ground Always 10 kΩ or higher
      H97-56 (SPD)*2 - Body ground Always 10 kΩ or higher

      • *1: w/o Navigation System

      • *2: w/ Navigation System

      Result
      Result Proceed to
      OK (w/o Navigation System) A
      OK (w/ Navigation System) B
      NG C

    A

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    B

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  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
      H114-12 - Body ground Telematics system*1 A
      H115-19 - Body ground Vehicle proximity notification system*2 B
      H115-21 - Body ground Audio and visual system*3 or Navigation system*4 C

      • *1: w/ Telematics Transceiver

      • *2: w/ Vehicle Proximity Notification System

      • *3: w/o Navigation System

      • *4: w/ Navigation System


    B

    CHECK HARNESS AND CONNECTOR (VEHICLE APPROACHING SPEAKER CONTROLLER CIRCUIT) Click here

    C

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT) Click here

    A

  12. CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT)


    1. Disconnect the H159 DCM (telematics transceiver) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H159-10 (SPDP) - Body ground Always 10 kΩ or higher

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  13. CHECK HARNESS AND CONNECTOR (VEHICLE APPROACHING SPEAKER CONTROLLER CIRCUIT)


    1. Disconnect the H216 vehicle approaching speaker controller connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H216-6 (SPD) - Body ground Always 10 kΩ or higher

    OK

    REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the H99*1 or H87*2 stereo component amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H99-17 (SPD)*1 - Body ground Always 10 kΩ or higher
      H87-11 (SPD)*2 - Body ground Always 10 kΩ or higher

      • *1: w/ Navigation System

      • *2: w/o Navigation System


    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR