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*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 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

  1. for 2AR-FXE

    A011Y2HE01

INSPECTION PROCEDURE

PROCEDURE

  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)

    1. Disconnect the I18 combination meter assembly connector.

      A011WY8E07

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      I18-9 (+S) - Body ground Power switch on (IG) 4.5 to 14 V
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      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. Reconnect the I18 combination meter assembly connector.

    2. Disconnect the A28 skid control ECU connector.

      A011WEWE01

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A28-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)
    NG

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

    OK

  3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)

    1. Check the input waveform.

      A011YQ4E03

      1. Reconnect the A28 skid control ECU connector.

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

      3. Connect an oscilloscope to terminal I18-8 (SI) and body ground.

      4. Turn the power switch on (IG).

      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 Wheel being rotated
        Text in Illustration
        *a

        Component with harness connected

        (Combination Meter Assembly)
        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.

    NG

    REPLACE BRAKE BOOSTER ASSEMBLY Click here

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

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

    1. Disconnect the I18 combination meter assembly and A28 skid control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A28-11 (SP1) - I18-8 (SI) Always Below 1 Ω
      A28-11 (SP1) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE BRAKE BOOSTER ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR)

    1. Disconnect the I124 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I18-9 (+S) - I124-18 Always Below 1 Ω
      I18-9 (+S) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)

    1. Inspect for a short in the circuit that is connected to the junction block 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. Disconnect the I124 junction connector.

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        I124-19 - Body ground Power switch on (IG) 4.5 to 14 V
        I124-17 - Body ground Power switch on (IG) 4.5 to 14 V
        I124-16 - Body ground Power switch on (IG) 4.5 to 14 V
        I124-20 - Body ground Power switch on (IG) 4.5 to 14 V
        I124-21 - Body ground Power switch on (IG) 4.5 to 14 V
        I124-22 - Body ground Power switch on (IG) 4.5 to 14 V
        Result
        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is not present in one circuit. (DCM (Telematics transceiver) circuit B
        Voltage is present in all the circuits. C
    B

    CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT) Click here

    C

    REPLACE JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE)

    A

  7. SYSTEM CHECK

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

      Result
      Tester Connection System that uses the circuit Proceed to
      I124-19 - Body ground Audio/Visual system*1 A
      I124-17 - Body ground Audio/Visual system*2, *3, or *4 Navigation system*5 B
      I124-16 - Body ground Lighting system*6 C
      I124-21 - Body ground Hybrid control system D
      I124-22 - Body ground Vehicle proximity notification system*7 E

      • *1: for 10 Speakers

      • *2: for Radio Receiver Type

      • *3: for Radio and Display Type w/o Intuitive Parking Assist System

      • *4: for Radio and Display Type w/ Intuitive Parking Assist System

      • *5: for Navigation Receiver Type

      • *6: w/ Automatic Headlight Beam Level Control System

      • *7: w/ Vehicle Proximity Notification System

    B

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

    C

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

    D

    CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU ASSEMBLY CIRCUIT) Click here

    E

    CHECK HARNESS AND CONNECTOR (VEHICLE APPROACHING SPEAKER CONTROLLER CIRCUIT) Click here

    A

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

    1. Disconnect the I69 stereo component amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I69-11 (SPD) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

  9. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY CIRCUIT, NAVIGATION ECU SUB-ASSEMBLY CIRCUIT, RADIO AND DISPLAY RECEIVER ASSEMBLY CIRCUIT)

    1. Disconnect the I150 radio receiver assembly*1 or I67 navigation ECU sub-assembly*2, *3, or I155 radio and display receiver assembly*4

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I150-17 (SPD)*1 - Body ground Always 10 kΩ or higher
      I67-17 (SPD)*2 - Body ground Always 10 kΩ or higher
      I67-17 (SPD)*3 - Body ground Always 10 kΩ or higher
      I155-17 (SPD)*4 - Body ground Always 10 kΩ or higher

      • *1: for Radio Receiver Type

      • *2: for Navigation Receiver Type

      • *3: for Radio and Display Type w/ Intuitive Parking Assist System

      • *4: for Radio and Display Type w/o Intuitive Parking Assist System

      Result
      Result Proceed to
      OK (for Radio Receiver Type) A
      OK (for Navigation Receiver Type) B
      OK (for Radio and Display Type w/ Intuitive Parking Assist System) B
      OK (for Radio and Display Type w/o Intuitive Parking Assist System) C
      NG D
    B

    REPLACE NAVIGATION RECEIVER ASSEMBLY Click here

    C

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

    D

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE RADIO RECEIVER ASSEMBLY Click here

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

    1. Disconnect the A34 headlight leveling ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A34-16 (SPDR) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

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

    1. Disconnect the I3 power management control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I3-14 (SPDI) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU ASSEMBLY Click here

  12. CHECK HARNESS AND CONNECTOR (VEHICLE APPROACHING SPEAKER CONTROLLER CIRCUIT)

    1. Disconnect the I71 vehicle approaching speaker controller connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I71-6 (SPD) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER Click here

  13. CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT)

    1. Disconnect the I135 DCM (telematics transceiver) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I135-10 (SPDP) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here