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*. 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

B003M9LE01

CAUTION / NOTICE / HINT

Note


  • When replacing the combination meter assembly, make sure to replace it with a new one.

  • Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed.

  • w/ Smart Entry and Start System:

    Before replacing the certification ECU (smart key ECU assembly), refer to the smart entry and start system.

    Click here

  • w/ Navigation System:

    When replacing the navigation receiver assembly, it is necessary to perform the vehicle contract setting for Connected Services.

    Click here

  • w/ Audio and Visual System (for Radio and Display Type):

    When replacing the radio and display receiver assembly, it is necessary to perform the vehicle contract setting for Connected Services.

    Click here

PROCEDURE


  1. CHECK ECM


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. B003R15C38
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    5. Disconnect the G33 body ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G8-19 (+S) - Body ground Ignition switch ON 4.5 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. B003R15C38
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G33 body ECU connector.

    5. Disconnect the G49 ECM connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G8-19 (+S) - Body ground Ignition switch ON 4.5 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - CERTIFICATION ECU [SMART KEY ECU ASSEMBLY]) Click here

    OK

  3. CHECK BODY ECU


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. B003R15C38
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    5. Disconnect the G49 ECM connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G8-19 (+S) - Body ground Ignition switch ON 4.5 to 14 V
      Result
      Result Proceed to
      OK (w/ Navigation System) A
      OK (w/ Audio and Visual System [for Radio and Display Type]) B
      NG C

    B

    CHECK RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

    C

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

    A

  4. CHECK NAVIGATION RECEIVER ASSEMBLY


    1. B003R15C38
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    3. Disconnect the G49 ECM connector.

    4. Disconnect the G33 body ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G8-19 (+S) - Body ground Ignition switch ON 4.5 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NAVIGATION RECEIVER ASSEMBLY) Click here

    OK

  5. CHECK COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A4-14 (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

  6. CHECK COMBINATION METER ASSEMBLY (INPUT WAVEFORM)


    1. B003JXTC10
      *a

      Component with harness connected

      (Combination Meter Assembly)
      *b Waveform

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

    2. Connect an oscilloscope to terminal G8-18 (SI) and body ground.

    3. Check the signal waveform according to the condition(s) in the table below.

      Measurement Condition
      Item Condition
      Tester Connection G8-18 (SI) - Body ground
      Tool Setting 5 V/DIV, 20 ms./DIV
      Vehicle Condition Driving at approximately 20 km/h (12 mph)

      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.

      OK
      The waveform displayed is as shown in the illustration.
      Result
      Result
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here

  7. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. Disconnect the G8 combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    5. Disconnect the G33 body ECU connector.

    6. Disconnect the G49 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-19 (+S) - G49-10 (SPD) Always Below 1 Ω
      G8-19 (+S) or G49-10 (SPD) - Body ground Always 10 kΩ or higher
      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - CERTIFICATION ECU [SMART KEY ECU ASSEMBLY])


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. Disconnect the G8 combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    5. Disconnect the G33 body ECU connector.

    6. Disconnect the G49 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-19 (+S) - G16-7 (SPD) Always Below 1 Ω
      G8-19 (+S) or G16-7 (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

  9. CHECK RADIO AND DISPLAY RECEIVER ASSEMBLY


    1. B003R15C38
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

    2. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    3. Disconnect the G49 ECM connector.

    4. Disconnect the G33 body ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G8-19 (+S) - Body ground Ignition switch ON 4.5 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    GO TO STEP 5 Click here

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - RADIO AND DISPLAY RECEIVER ASSEMBLY) Click here

  10. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NAVIGATION RECEIVER ASSEMBLY)


    1. Disconnect the G8 combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.

    3. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    4. Disconnect the G33 body ECU connector.

    5. Disconnect the G49 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-19 (+S) - G41-17 (SPD) Always Below 1 Ω
      G8-19 (+S) or G41-17 (SPD) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NAVIGATION RECEIVER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the N34 combination meter assembly connector.

    2. Disconnect the A4 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
      G8-18 (SI) - A4-14 (SP1) Always Below 1 Ω
      G8-18 (SI) or A4-14 (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

  12. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - RADIO AND DISPLAY RECEIVER ASSEMBLY)


    1. Disconnect the G8 combination meter assembly connector.

    2. Disconnect the G100 radio and display receiver assembly connector.

    3. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    4. Disconnect the G33 body ECU connector.

    5. Disconnect the G49 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-19 (+S) - G100-17 (SPD) Always Below 1 Ω
      G8-19 (+S) or G100-17 (SPD) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  13. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BODY ECU)


    • *1: w/ Navigation System

    • *2: w/ Audio and Visual System (for Radio and Display Type)


    1. Disconnect the G8 combination meter assembly connector.

    2. Disconnect the G41 navigation receiver assembly connector.*1

    3. Disconnect the G100 radio and display receiver assembly connector.*2

    4. Disconnect the G16 certification ECU (smart key ECU assembly) connector.

    5. Disconnect the G33 body ECU connector.

    6. Disconnect the G49 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-19 (+S) - G33-5 (SPD) Always Below 1 Ω
      G8-19 (+S) or G33-5 (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