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

B007Y3NE02

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. B007ZKIC29
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the J10 combination meter assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      J10-19 (+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 - JUNCTION CONNECTOR) Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the J10 combination meter assembly connector.

    2. B007YYAC24
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

      Disconnect the A41 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
      A41-18 (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. B007XRQC32
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A41 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 J10-20 (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) Click here

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


    1. Disconnect the J10 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J10-20 (SI) - A41-18 (SP1) Always Below 1 Ω
      J10-20 (SI) or A41-18 (SP1) - 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 - JUNCTION CONNECTOR)


    1. Disconnect the J118 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J10-19 (+S) - J118-21 Always Below 1 Ω
      J10-19 (+S) or J118-21 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)


    1. Check 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.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      J118-16 - Body ground Engine switch on (IG) 4.5 to 14 V
      J118-17 - Body ground Engine switch on (IG) 4.5 to 14 V
      J118-19 - Body ground Engine switch on (IG) 4.5 to 14 V
      J118-20- Body ground Engine 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
      Result System that uses the circuit Proceed to
      J118-16 - Body ground SFI system A
      J118-20 - Body ground Entry and start system B
      J118-19 - Body ground Navigation system*1 or Audio and visual system*2 C
      J118-17 - Body ground Navigation system*1 or Audio and visual system*2 D

      • *1: w/ Navigation System

        *2: w/o Navigation System


    B

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - BODY GROUND) Click here

    C

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - BODY GROUND) Click here

    D

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - BODY GROUND) Click here

    A

  8. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. Disconnect the A37*1 or A46*2 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A37-39 (SPD) or J118-16 - Body ground*1 Always 10 kΩ or higher
      A46-44 (SPD) or J118-16 - Body ground*2 Always 10 kΩ or higher

      • *1: for 2GR-FKS

      • *2: for 8AR-FTS

      Result
      Result Proceed to
      OK (for 2GR-FKS) A
      OK (for 8AR-FTS) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - BODY GROUND)


    1. Disconnect the J41 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
      J41-19 (SPD) or J118-20 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  10. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - BODY GROUND)


    1. Disconnect the J50*1, *2 or J53*3 radio receiver assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J50-56 (SPD) or J118-19 - Body ground*1, *2 Always 10 kΩ or higher
      J53-17 (SPD) or J118-19 - Body ground*3 Always 10 kΩ or higher

      • *1: w/ Navigation System

        *2: w/ Audio and Visual System (for 12.3 Inch Display)

        *3: w/ Audio and Visual System (for 8 Inch Display)

      Result
      Result Proceed to
      OK (w/ Navigation System) A
      OK (w/ Audio and Visual System (for 12.3 Inch Display))
      OK (w/ Audio and Visual System (for 8 Inch Display)) 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. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - BODY GROUND)


    1. Disconnect the J66*1, *2 or J67*3 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
      J66-17 (SPD) or J118-17 - Body ground*1, *2 Always 10 kΩ or higher
      J67-11 (SPD) or J118-17 - Body ground*3 Always 10 kΩ or higher

      • *1: w/ Navigation System

        *2: w/ Audio and Visual System (for 12.3 Inch Display)

        *3: w/ Audio and Visual System (for 8 Inch Display)

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR