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 2GR-FE

    A01EXXFE04

  2. for 2AR-FE

    A01ETMEE01

  3. for 1AZ-FE

    A01EWWME01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A01EWZEE07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the I18 combination meter assembly connector.

    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 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 - JUNCTION CONNECTOR) Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the I18 combination meter assembly connector.

    2. A01EXFAE09
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

      Disconnect the A49 skid control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A49-2 (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. A01EUU5E04
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the input waveform.


      1. Reconnect the A49 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 ignition switch to 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 Wheel being rotated
        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.


    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    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 A49 skid control ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A49-2 (SP1) - I18-8 (SI) Always Below 1 Ω
      A49-2 (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 - 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
        I124-21 - Body ground Ignition switch ON 4.5 to 14 V
        I124-19 - Body ground Ignition switch ON 4.5 to 14 V
        I124-17 - Body ground Ignition switch ON 4.5 to 14 V
        I124-20 - Body ground Ignition switch ON 4.5 to 14 V
        I124-16 - Body ground Ignition switch ON 4.5 to 14 V
        I124-16 - Body ground Ignition switch ON 4.5 to 14 V
        I124-16 - 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 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
      I124-21 - Body ground Smart Entry and start system*1 A
      I124-19 - Body ground Audio/Visual system*2 B
      I124-17 - Body ground Audio/Visual system*3, *5 or Navigation system*4 C
      I124-20 - Body ground Auto wiper system*7 D
      I124-16 - Body ground SFI system E
      I124-16 - Body ground Lighting system*6 E
      I124-16 - Body ground U660E automatic transaxle system E

      • *1: w/ Smart Entry and Start System

      • *2: for 10 Speakers

      • *3: for Radio Receiver Type

      • *4: for Navigation Receiver Type

      • *5: for Radio and Display Type

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

      • *7: w/ Auto Wiper System


    B

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

    C

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

    D

    CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT) Click here

    E

    SYSTEM CHECK Click here

    A

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


    1. Disconnect the I78 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
      I78-27 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  9. 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

  10. 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 connector*1, I67 navigation ECU sub-assembly*2, or I155 radio and display receiver assembly*3 connector.

    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
      I155-17 (SPD)*3 - Body ground Always 10 kΩ or higher

      • *1: for Radio Receiver Type

      • *2: for Navigation Receiver Type

      • *3: for Radio and Display Type

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

    B

    REPLACE NAVIGATION ECU SUB-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

  11. CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT)


    1. Disconnect the I72 windshield wiper relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I72-24 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY Click here

  12. 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
      I124-16 - Body ground SFI system A
      I124-16 - Body ground Lighting system*1 B
      I124-16 - Body ground U660E automatic transaxle system C

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


    B

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

    C

    CHECK HARNESS AND CONNECTOR (TCM CIRCUIT) Click here

    A

  13. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)


    1. Disconnect the A25*1 or A74*2 ECM connector.


      • *1: for 2AR-FE, for 2GR-FE

      • *2: for 1AZ-FE

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A25-57*1 (SPD) - Body ground Always 10 kΩ or higher
      A25-10*2 (SPD) - Body ground Always 10 kΩ or higher
      A74-8*3 (SPD) - Body ground Always 10 kΩ or higher

      • *1: for 2AR-FE

      • *2: for 2GR-FE

      • *3: for 1AZ-FE

      Result
      Result Proceed to
      OK (for 2AR-FE) A
      OK (for 2GR-FE) B
      OK (for 1AZ-FE) C
      NG D

    B

    REPLACE ECM (for 2GR-FE) Click here

    C

    REPLACE ECM (for 1AZ-FE) Click here

    D

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE ECM (for 2AR-FE) Click here

  14. 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

  15. CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)


    1. Disconnect the E7 TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E7-3 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE TCM Click here