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 sensor signal*1. The vehicle speed sensor 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 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 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. The combination meter assembly components such as the speedometer operate using data received via CAN communication.

WIRING DIAGRAM

A0117DEE01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT COMBINATION METER ASSEMBLY (INPUT VOLTAGE)


    1. A011AQHE20
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D1-16 (+S) - Body ground Ignition switch ON 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. A01177EE05
      Text in Illustration
      *A for LHD
      *B for RHD
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

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

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

      Standard Voltage
      for LHD
      Tester Connection Switch Condition Specified Condition
      A16-11 (SP1) - Body ground Ignition switch ON 11 to 14 V
      for RHD
      Tester Connection Switch Condition Specified Condition
      A17-11 (SP1) - Body ground Ignition switch ON 11 to 14 V

    NG

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

    OK

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


    1. A0118PYE01
      Text in Illustration
      *1

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


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

      2. Connect an oscilloscope to terminal D1-17 (SI) and body ground.

      3. Turn the ignition switch to ON.

      4. Turn the wheel slowly.

      5. 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 approximately 20 km/h (12 mph)
        OK
        The waveform is displayed as shown in the illustration.

        Tech Tips

        As the vehicle speed increases, the cycle of the waveform narrows.


    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

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


    1. A011BD1E03
      Text in Illustration
      *A for LHD
      *B for RHD
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *b

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

      Disconnect the combination meter assembly connector.

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

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      D1-17 (SI) - A16-11 (SP1) Always Below 1 Ω
      D1-17 (SI) or A16-11 (SP1) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      D1-17 (SI) - A17-11 (SP1) Always Below 1 Ω
      D1-17 (SI) or A17-11 (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. A011BHVE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)
      *b

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D1-16 (+S) - D68-71 Always Below 1 Ω
      D1-16 (+S) or D68-71 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. SYSTEM CHECK


    1. Check the vehicle specifications.

      Result
      Result Proceed to
      w/ Rain Sensor A
      w/o Rain Sensor B

    B

    SYSTEM CHECK Click here

    A

  7. INSPECT WINDSHIELD WIPER RELAY ASSEMBLY


    1. A011BFPE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)

      Disconnect the junction connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D68-81 - Body ground Ignition switch ON 4.5 to 14 V

    NG

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

    OK

  8. SYSTEM CHECK


    1. Check the vehicle specifications.

      Result
      Result Proceed to
      w/ Entry and Start System A
      w/o Entry and Start System B

    B

    INSPECT ECM Click here

    A

  9. INSPECT POWER MANAGEMENT CONTROL ECU


    1. A011BFPE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)

      Disconnect the junction connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D68-91 - Body ground Ignition switch ON 4.5 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - POWER MANAGEMENT CONTROL ECU) Click here

    OK

  10. INSPECT ECM


    1. A011BFPE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)

      Disconnect the junction connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D68-61 - Body ground Ignition switch ON 4.5 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - ECM) Click here

    OK

    REPLACE JUNCTION CONNECTOR

  11. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - WINDSHIELD WIPER RELAY ASSEMBLY)


    1. A011AREE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)
      *b

      Front view of wire harness connector

      (to Windshield Wiper Relay Assembly)

      Disconnect the junction connector.

    2. Disconnect the windshield wiper relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D68-81 - D41-19 (SPD) Always Below 1 Ω
      D68-81 or D41-19 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY Click here

  12. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - POWER MANAGEMENT CONTROL ECU)


    1. A0117FZE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)
      *b

      Front view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the junction connector.

    2. Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D68-91 - D38-23 (SPD) Always Below 1 Ω
      D68-91 or D38-23 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

  13. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - ECM)


    1. Disconnect the junction connector.

      A0118G3E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Junction Connector)

      		 *b

      Front view of wire harness connector

      (to ECM)

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D68-61 - A18-38 (SPD) Always Below 1 Ω
      D68-61 or A18-38 (SPD) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      NG A
      OK (for 1KR-FE) B
      OK (for 1NR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR