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*1. 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

A01EKW2E01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A01EJSCE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the E1 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E1-16 (+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 - E31 JUNCTION CONNECTOR) Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the E1 connector.

    2. A01EJ70E04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      Disconnect the A42 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A42-33 (SP1) - Body ground Ignition switch ON 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. A01EMPRE02
      Text in Illustration
      *1

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A42 connector.

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

      3. Connect an oscilloscope to terminal E1-8 (SI) and body ground.

      4. Turn the ignition switch ON.

      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 Driving at approx. 20 km/h (12 mph)
        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.


    NG

    REPLACE SKID CONTROL ECU Click here

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

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


    1. Disconnect the E1 and A42 connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A42-33 (SP1) - E1-8 (SI) Always Below 1 Ω
      A42-33 (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 - E31 JUNCTION CONNECTOR)


    1. Disconnect the E31 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E1-16 (+S) - E31-19 Always Below 1 Ω
      E1-16 (+S) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK D57, E31 JUNCTION CONNECTOR


    1. Inspect for a short in the circuit that is 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. A01EM6KE08
        Text in Illustration
        *1

        Front view of wire harness connector

        (to Junction Connector)

        Disconnect the D57 junction connector.

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        E31-20 - Body ground Ignition switch ON 4.5 to 14 V
        E31-21 - Body ground Ignition switch ON 4.5 to 14 V
        D57-13 - Body ground Ignition switch ON 4.5 to 14 V
        D57-14 - Body ground Ignition switch ON 4.5 to 14 V
        Result
        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all the circuits. B

    B

    REPLACE D57, E31 JUNCTION CONNECTOR

    A

  7. CHECK HARNESS AND CONNECTOR (D57 JUNCTION CONNECTOR - D55 JUNCTION CONNECTOR)


    1. Disconnect the D55 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D57-14 - D55-17 Always Below 1 Ω
      D57-14 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK A43 JUNCTION CONNECTOR


    1. Inspect for a short in the circuit that is connected to A43 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. A01EM6KE09
        Text in Illustration
        *1

        Front view of wire harness connector

        (to Junction Connector)

        Disconnect the A43 junction connector.

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        A43-16 - Body ground Ignition switch ON 4.5 to 14 V
        A43-17 - Body ground Ignition switch ON 4.5 to 14 V
        A43-18 - Body ground Ignition switch ON 4.5 to 14 V
        Result
        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all the circuits. B

    B

    REPLACE A43 JUNCTION CONNECTOR

    A

  9. SYSTEM CHECK


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

      Result
      Tester Connection System that Uses the Circuit Proceed to
      D57-13 - Body ground Smart Entry and Start System*1 A
      E31-21 - Body ground Audio and Visual System (Stereo Component Amplifier Assembly)*2 B
      E31-20 - Body ground Audio and Visual System*3 or Navigation System*4 C
      D57-14 - Body ground SFI System, Automatic Transaxle System, or Lighting System*3 D

      • *1: w/ Smart Entry and Start System

      • *2: for 13 Speakers

      • *3: for Radio and Display Type

      • *4: for Navigation Receiver Type


    B

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

    C

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

    D

    SYSTEM CHECK Click here

    A

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


    1. Disconnect the D43 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D43-23 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

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


    1. Disconnect the E14 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E14-11 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

  12. CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY CIRCUIT, NAVIGATION RECEIVER ASSEMBLY CIRCUIT)


    1. Disconnect the E42*1 or E40*2 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E42-17 (SPD)*1 - Body ground Always 10 kΩ or higher
      E40-17 (SPD)*2 - Body ground Always 10 kΩ or higher

      • *1: for Radio and Display Type

      • *2: for Navigation Receiver Type

      Result
      Result Proceed to
      OK (for Radio and Display Type) A
      OK (for Navigation Receiver Type) B
      NG C

    B

    REPLACE NAVIGATION RECEIVER ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

  13. SYSTEM CHECK


    1. Select the circuit in which is not present voltage in step 8.

      Result
      Tester Connection System that Uses the Circuit Proceed to
      A43-17 - Body ground SFI System A
      A43-16 - Body ground U760E Automatic Transaxle System, U760F Automatic Transaxle System B
      A43-18 - Body ground Lighting System C

    B

    CHECK HARNESS AND CONNECTOR (TCM CIRCUIT) Click here

    C

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

    A

  14. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)


    1. Disconnect the A49 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A49-15 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here

  15. CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)


    1. Disconnect the B40 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B40-3 (SPD) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      OK (for U760E Automatic Transaxle System) A
      OK (for U760F Automatic Transaxle System) B
      NG C

    B

    REPLACE TCM Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE TCM Click here

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


    1. Disconnect the A40 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A40-16 (SPDR) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here