METER / GAUGE SYSTEM Speed Signal Circuit

DTC Code DTC Name
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.

  • *a: This vehicle speed sensor signal is created by the skid control ECU. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some systems, vehicle speed information may be received via CAN communication.

Tip:

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

E292674E03

CAUTION / NOTICE / HINT

Note:

When it is necessary to replace the combination meter assembly, be sure to replace it with a new one.

PROCEDURE

  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)

    1. E188997C17

      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the E12 combination meter assembly connector.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      E12-22 (+S) - Body ground

      Ignition switch ON

      4.5 to 14 V
      Tip:

      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 - NO. 5 JUNCTION CONNECTOR)Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

    1. Reconnect the E12 combination meter assembly connector.

    2. Disconnect the A39 skid control ECU connector.

    3. C261861C16

      *a

      Front view of wire harness connector (to Brake Actuator Assembly (Skid Control ECU))

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A39-2 (SP1) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL AND ECM)Click here

    OK

  3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)

    1. E262405C17

      *a

      Component with harness connected

      (Combination Meter Assembly)

      Reconnect the A39 skid control ECU connector.

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

    3. Connect an oscilloscope to terminal E12-21 (SI) and body ground.

    4. Turn the ignition switch to ON.

    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

      Ignition switch ON, wheel being rotated

      OK

      The waveform is similar to that shown in the illustration.

      Tip:

      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 - SKID CONTROL AND ECM)

    1. Disconnect the E12 combination meter assembly connector.

    2. Disconnect the A34 ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E12-21 (SI) - A39-2 (SP1)

      Always

      Below 1 Ω

      E12-21 (SI) - A34-41 (SPD)

      Always

      Below 1 Ω

      E12-21 (SI) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT ECM (OUTPUT VOLTAGE)

    1. Reconnect the E34 ECM connector.

    2. C261861C16

      *a

      Front view of wire harness connector (to Brake Actuator Assembly (Skid Control ECU))

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A39-2 (SP1) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE COMBINATION METER ASSEMBLY

    Click here

    NG

    REPLACE ECM

    Click here

  6. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NO. 5 JUNCTION CONNECTOR)

    1. Disconnect the E22 No. 5 junction connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E12-22 (+S) - E22-5

      Always

      Below 1 Ω

      E12-22 (+S) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  7. CHECK NO. 5 JUNCTION CONNECTOR

    1. Check for a short in the wire harness and connectors connected to the No. 5 junction connector shown in the wiring diagram.

      Tip:

      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 E23 No. 5 junction connector.

      2. E284758C01

        *a

        Component without harness connected

        (No. 5 Junction Connector)

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

        Standard Voltage

        Tester Connection

        Condition

        Specified Condition

        E22-6 - Body ground*1

        Ignition switch ON

        4.5 to 14 V

        E22-7 - Body ground*2

        Ignition switch ON

        4.5 to 14 V

        E23-6 - Body ground*3

        Ignition switch ON

        4.5 to 14 V

        E23-7 - Body ground*1

        Ignition switch ON

        4.5 to 14 V

        • *1: w/ Entry and Start System

        • *2: w/ Audio and Visual System

        • *3: for Multi-mode Manual Transaxle

    Result

    Result

    Proceed to

    Voltage is not present in one circuit.

    A

    Voltage is present in all of the circuits.

    B
    B

    REPAIR OR REPLACE INSTRUMENT PANEL WIRE (NO. 5 JUNCTION CONNECTOR)

    A

  8. SYSTEM CHECK

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

    Result

    Tester Connection

    System that Uses the Circuit

    Proceed to

    E22-6 - Body ground

    Entry and start system*1

    A

    E22-7 - Body ground

    Audio and visual system*2

    B

    E23-6 - Body ground

    Multi-mode manual transaxle system*3

    C

    E23-7 - Body ground

    Power door lock control system*1

    D

    • *1: w/ Entry and Start System

    • *2: w/ Audio and Visual System

    • *3: for Multi-mode Manual Transaxle

    B

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

    C

    CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)Click here

    D

    CHECK HARNESS AND CONNECTOR (BODY ECU CIRCUIT)Click here

    A

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

    1. Disconnect the E49 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

      E49-7 (SPD) - 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 AND DISPLAY RECEIVER ASSEMBLY CIRCUIT, RADIO RECEIVER ASSEMBLY CIRCUIT)

    1. Disconnect the E32 radio and display receiver assembly*1 or E55 radio receiver assembly*2 connector.

      • *1: for Radio and Display Type

      • *2: for Radio Receiver Type

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E32-16 (SPD) - Body ground*1

      Always

      10 kΩ or higher

      E55-16 (SPD) - Body ground*2

      Always

      10 kΩ or higher

      • *1: for Radio and Display Type

      • *2: for Radio Receiver Type

    Result

    Result

    Proceed to

    OK (for Radio and Display Type)

    A

    OK (for Radio Receiver Type)

    B

    NG

    C
    A

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

    Click here

    B

    REPLACE RADIO RECEIVER ASSEMBLY

    Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)

    1. Disconnect the A27 TCM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A27-23 (SPD) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE TCM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  12. CHECK HARNESS AND CONNECTOR (BODY ECU CIRCUIT)

    1. Disconnect the E46 body ECU connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E46-5 (SPD) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE BODY ECU

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR