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

A001Y4BE04

CAUTION / NOTICE / HINT

Note


  • Before replacing the ECM or certification ECU (smart key ECU assembly) refer to Service Bulletin.

  • When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A001TN4C47
      *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
      F4-6 (+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.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU) Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the F4 combination meter assembly connector.

    2. A001VE1C27
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A42-34 (SP1) - Body ground Ignition switch ON 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. A001WYNC81
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A42 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 F4-5 (SI) and body ground.

      4. Turn the ignition switch 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.

        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 ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here

    C

    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 F4 combination meter assembly connector.

    2. Disconnect the A42 brake actuator 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
      F4-5 (SI) - A42-34 (SP1) Always Below 1 Ω
      F4-5 (SI) - 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 - EACH ECU)


    1. Disconnect the A38 ECM connector.

    2. Disconnect the F76 stereo component amplifier assembly connector.*2

    3. Disconnect the F47 radio receiver assembly connector.*3

    4. Disconnect the F125 radio and display receiver assembly connector.*4

    5. Disconnect the F1 certification ECU (smart key ECU assembly) connector.*5

    6. Disconnect the F56 auto wiper ECU connector.*6

    7. Disconnect the F51 telematics transceiver connector.*1

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


      • *1: w/ Telematics Transceiver

      • *2: for Separate Type Amplifier

      • *3: for Radio Receiver Type

      • *4: for Radio and Display Receiver Type

      • *5: w/ Entry and Start System

      • *6: w/ Auto Wiper System

      Standard Resistance
      Tester Connection Condition Specified Condition
      F4-6 (+S) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT ECM (SHORT CIRCUIT IN ECM)


    1. Disconnect the A38 ECM connector.

    2. Reconnect the F76 stereo component amplifier assembly connector.*1

    3. Reconnect the F47 radio receiver assembly connector.*2

    4. Reconnect the F125 radio and display receiver assembly connector.*3

    5. Reconnect the F1 certification ECU (smart key ECU assembly) connector.*4

    6. Reconnect the F56 auto wiper ECU connector.*5

    7. Reconnect the F51 telematics transceiver*6 connector.

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


      • *1: for Separate Type Amplifier

      • *2: for Radio Receiver Type

      • *3: for Radio and Display Receiver Type

      • *4: w/ Entry and Start System

      • *5: w/ Auto Wiper System

      • *6: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the ECM.

      Result
      Result Proceed to
      OK (for 8NR-FTS) A
      OK (for 3ZR-FAE) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

  7. CONFIRM MODEL


    1. Choose the model to be inspected.

      Result
      Result Proceed to
      for Separate Type Amplifier A
      Except Separate Type Amplifier B

    B

    CONFIRM MODEL Click here

    A

  8. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)


    1. Disconnect the F76 stereo component amplifier assembly connector.

    2. Reconnect the F47 radio receiver assembly connector.*1

    3. Reconnect the F125 radio and display receiver assembly connector.*2

    4. Reconnect the F1 certification ECU (smart key ECU assembly) connector.*3

    5. Reconnect the F56 auto wiper ECU connector.*4

    6. Reconnect the F51 telematics transceiver*5 connector.

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


      • *1: for Radio Receiver Type

      • *2: for Radio and Display Receiver Type

      • *3: w/ Entry and Start System

      • *4: w/ Auto Wiper System

      • *5: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    NG

  9. CONFIRM MODEL


    1. Choose the model to be inspected.

      Result
      Result Proceed to
      for Radio Receiver Type A
      Except Radio Receiver Type B

    B

    CONFIRM MODEL Click here

    A

  10. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY)


    1. Disconnect the F47 radio receiver assembly connector.

    2. Reconnect the F1 certification ECU (smart key ECU assembly) connector.*1

    3. Reconnect the F56 auto wiper ECU connector.*2

    4. Reconnect the F51 telematics transceiver*3 connector.

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


      • *1: w/ Entry and Start System

      • *2: w/ Auto Wiper System

      • *3: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    NG

  11. CONFIRM MODEL


    1. Choose the model to be inspected.

      Result
      Result Proceed to
      for Radio and Display Receiver Type A
      Except Radio and Display Receiver Type B

    B

    CONFIRM MODEL Click here

    A

  12. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO AND DISPLAY RECEIVER ASSEMBLY)


    1. Disconnect the F125 radio and display receiver assembly connector.

    2. Reconnect the F1 certification ECU (smart key ECU assembly) connector.*1

    3. Reconnect the F56 auto wiper ECU connector.*2

    4. Reconnect the F51 telematics transceiver*3 connector.

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


      • *1: w/ Entry and Start System

      • *2: w/ Auto Wiper System

      • *3: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

    NG

  13. CONFIRM MODEL


    1. Choose the model to be inspected.

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

    B

    CONFIRM MODEL Click here

    A

  14. INSPECT CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (SHORT CIRCUIT IN CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))


    1. Disconnect the F1 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the F56 auto wiper ECU connector.*1

    3. Reconnect the F51 telematics transceiver*2 connector.

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


      • *1: w/ Auto Wiper System

      • *2: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    NG

  15. CONFIRM MODEL


    1. Choose the model to be inspected.

      Result
      Result Proceed to
      w/ Auto Wiper System A
      w/o Auto Wiper System B

    B

    REPLACE TELEMATICS TRANSCEIVER Click here

    A

  16. INSPECT AUTO WIPER ECU (SHORT CIRCUIT IN AUTO WIPER ECU)


    1. Disconnect the F56 auto wiper ECU connector.

    2. Reconnect the F51 telematics transceiver*1 connector.

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


      • *1: w/ Telematics Transceiver

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F4-6 (+S) - Body ground Ignition switch ON 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AUTO WIPER ECU Click here

    NG

    REPLACE TELEMATICS TRANSCEIVER Click here