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*1. 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

    A01CB81E05

  2. for 2AZ-FE

    A01CC9KE03

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    1. A01CBK7E29

      Disconnect the G19 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G19-24 (+S) - Body ground Engine switch on (IG) 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 - NO. 2 JUNCTION BLOCK) Click here

    OK

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)


    1. Reconnect the G19 connector.

    2. A01CEY7E01

      Disconnect the A10 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A10-33 (SP1) - Body ground Engine switch on (IG) 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. A01CFDDE03

      Check the input waveform.


      1. Reconnect the A10 connector.

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

      3. Connect an oscilloscope to terminal G19-23 (SI) and body ground.

      4. Turn the engine switch on (IG).

      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 Driving at approx. 20 km/h (12 mph)
        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.


    NG

    REPLACE SKID CONTROL ECU Click here

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

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


    1. Disconnect the G19 and A10 connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A10-33 (SP1) - G19-23 (SI) Always Below 1 Ω
      A10-33 (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 - NO. 2 JUNCTION BLOCK)


    1. Disconnect the LA to LG No. 2 junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G19-24 (+S) - LD-4*1 Always Below 1 Ω
      G19-24 (+S) - LA-4*2 Always Below 1 Ω
      G19-24 (+S) - Body ground Always 10 kΩ or higher

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (NO. 2 JUNCTION BLOCK)


    1. Inspect for a short in the circuit that is connected to the No. 2 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 LH to LM No. 2 junction block connector.

        A01CALBE02

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        LB-4 - Body ground Engine switch on (IG) 4.5 to 14 V
        LC-4 - Body ground Engine switch on (IG) 4.5 to 14 V
        LH-4 - G19-24 (+S) Engine switch on (IG) 4.5 to 14 V
        Result
        Result Proceed to
        Voltage is present in all the circuits. A
        Voltage is not present (LC-4 - Body ground). B
        Voltage is not present (LB-4 - Body ground). C

    B

    CHECK HARNESS AND CONNECTOR (NO. 2 JUNCTION BLOCK - JUNCTION BLOCK) Click here

    C

    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT) Click here

    A

  7. CHECK HARNESS AND CONNECTOR (NO. 2 JUNCTION BLOCK - WINDSHIELD WIPER RELAY)


    1. Disconnect the G12 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G12-19 (SPD) - LA-4*1 Always 10 kΩ or higher
      G12-19 (SPD) - LH-5*2, *3 Always 10 kΩ or higher

      • *1: for LHD

      • *2: for RHD

      • *3: for 2AZ-FE (w/ Auto Wiper System)


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. REPLACE WINDSHIELD WIPER RELAY


    1. Replace the windshield wiper relay with a new or a known good one Click here for RHD, Click here for LHD).

      OK
      The operation of other systems that use the speed signal returns to normal.

    NG

    REPLACE NO. 2 JUNCTION BLOCK

    OK

    END

  9. CHECK HARNESS AND CONNECTOR (NO. 2 JUNCTION BLOCK - JUNCTION BLOCK)


    1. Disconnect the RA to RG junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      LC-4 - RC-8 Always Below 1 Ω
      RC-8 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (JUNCTION BLOCK)


    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 RA to RG junction block connector.

        A01CFK7E03

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        RB-8 - Body ground Engine switch on (IG) 4.5 to 14 V
        RB-8 - Body ground Engine switch on (IG) 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 BLOCK

    A

  11. SYSTEM CHECK


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

      Result
      Tester Connection System that Uses the Circuit Proceed to
      LB-4 - Body ground Smart entry and start system (for start function) A
      LC-4 - Body ground SFI system B
      LC-4 - Body ground U660E automatic transaxle system*1 C
      LC-4 - Body ground Lighting system*2 D
      LH-4 - Body ground Navigation system*3, *4 E

      • *1: for U660E Automatic Transaxle System

      • *2: w/ Automatic Type Headlight Beam Level Control (w/o AFS)

      • *3: w/ Navigation System (w/ Front Center Speaker)

      • *4: w/ Navigation System (w/o Front Center Speaker)


    B

    CHECK HARNESS AND CONNECTOR (ECM CIRCUIT) Click here

    C

    CHECK HARNESS AND CONNECTOR (TCM CIRCUIT) Click here

    D

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

    E

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT, NAVIGATION ECU SUB-ASSEMBLY CIRCUIT) Click here

    A

  12. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)


    1. Disconnect the G50 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G50-9 (SPD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU Click here

  13. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)


    1. Disconnect the A8 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A8-8 (SPD) - Body ground Always 10 kΩ or higher

    B

    REPLACE ECM (for 2AZ-FE) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE ECM (for 2GR-FE) Click here

  14. CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)


    1. Disconnect the D4 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D4-3 (SPD1) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE TCM (for U660E) Click here

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


    1. Disconnect the A34 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

  16. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT, NAVIGATION ECU SUB-ASSEMBLY CIRCUIT)


    1. Disconnect the F26*1, F23*1, or F36*2 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F26-7 (SPD)*1 - Body ground Always 10 kΩ or higher
      F23-56 (SPD)*1 - Body ground Always 10 kΩ or higher
      F36-17 (SPD)*2 - Body ground Always 10 kΩ or higher

      • *1: w/ Navigation System (w/ Front Center Speaker)

      • *2: w/ Navigation System (w/o Front Center Speaker)

      Result
      Result Proceed to
      OK (for Stereo Component Amplifier Assembly Circuit) A
      OK (for Navigation ECU Sub-assembly Circuit) B
      NG C

    B

    REPLACE NAVIGATION ECU SUB-ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here