METER / GAUGE SYSTEM Headup Display Malfunction

DESCRIPTION

This circuit is the power source circuit for the headup display. This circuit provides two types of power sources; one is a constant power source mainly used as a backup power source, and the other is a power source mainly used for signal transmission.

WIRING DIAGRAM

A019OFRE10

INSPECTION PROCEDURE

Tech Tips

Before starting the following inspection, confirm the headup display position illuminance, then perform the on-vehicle inspection Click here.

PROCEDURE


  1. SYSTEM CHECK


    1. Check the symptom of the headup display.

      Result
      Result Proceed to
      Headup display does not operate at all. A
      Cruise information display does not change. B

    B

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

    A

  2. CHECK HARNESS AND CONNECTOR (HEADUP DISPLAY CIRCUIT)


    1. A019L5IE22
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Headup Display)

      Disconnect the H1 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H1-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      H1-2 (B) - Body ground Always 11 to 14 V
      H1-3 (ACC) - Body ground Engine switch on (ACC) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H1-5 (ES) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (HEADUP DISPLAY - SATELLITE SWITCH SET)


    1. for LHD


      1. Disconnect the H1 and F23 connectors.

        A019LRFE02

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        H1-14 (HUDO) - F23-7 (CH) Always Below 1 Ω
        H1-14 (HUDO) - Body ground Always 10 kΩ or higher
        H1-15 (HUDU) - F23-6 (HDU) Always Below 1 Ω
        H1-15 (HUDU) - Body ground Always 10 kΩ or higher
        H1-16 (HUDD) - F23-5 (HDD) Always Below 1 Ω
        H1-16 (HUDD) - Body ground Always 10 kΩ or higher
        H1-12 (ILU) - F23-4 (ILU) Always Below 1 Ω
        H1-12 (ILU) - Body ground Always 10 kΩ or higher
        H1-13 (ILD) - F23-3 (ILD) Always Below 1 Ω
        H1-13 (ILD) - Body ground Always 10 kΩ or higher

    2. for RHD


      1. A019LRFE03
        Text in Illustration
        *1

        Front view of wire harness connector

        (to Headup Display)
        *2

        Front view of wire harness connector

        (to Satellite Switch Set)

        Disconnect the H1 and F23 connectors.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        H1-14 (HUDO) - F23-2 (CH) Always Below 1 Ω
        H1-14 (HUDO) - Body ground Always 10 kΩ or higher
        H1-15 (HUDU) - F23-3 (HDU) Always Below 1 Ω
        H1-15 (HUDU) - Body ground Always 10 kΩ or higher
        H1-16 (HUDD) - F23-4 (HDD) Always Below 1 Ω
        H1-16 (HUDD) - Body ground Always 10 kΩ or higher
        H1-12 (ILU) - F23-5 (ILU) Always Below 1 Ω
        H1-12 (ILU) - Body ground Always 10 kΩ or higher
        H1-13 (ILD) - F23-6 (ILD) Always Below 1 Ω
        H1-13 (ILD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT SATELLITE SWITCH SET


    1. for LHD


      1. Disconnect the H1 connector.

        A019K62E02

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

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        2 (E) - 3 (ILD) Display contrast down switch pressed Below 1 Ω
        2 (E) - 3 (ILD) Display contrast down switch not pressed 10 kΩ or higher
        2 (E) - 4 (ILU) Display contrast up switch pressed Below 1 Ω
        2 (E) - 4 (ILU) Display contrast up switch not pressed 10 kΩ or higher
        2 (E) - 5 (HDD) Headup display position down switch pressed Below 1 Ω
        2 (E) - 5 (HDD) Headup display position down switch not pressed 10 kΩ or higher
        2 (E) - 6 (HDU) Headup display position up switch pressed Below 1 Ω
        2 (E) - 6 (HDU) Headup display position up switch not pressed 10 kΩ or higher
        2 (E) - 7 (CH) Headup display on switch pressed Below 1 Ω
        2 (E) - 7 (CH) Headup display on switch not pressed 10 kΩ or higher

    2. for RHD


      1. A019K62E03
        Text in Illustration
        *1

        Component without harness connected

        (Satellite Switch Set)

        Disconnect the H1 connector.

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

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        6 (ILD) - 7 (E) Display contrast down switch pressed Below 1 Ω
        6 (ILD) - 7 (E) Display contrast down switch not pressed 10 kΩ or higher
        5 (ILU) - 7 (E) Display contrast up switch pressed Below 1 Ω
        5 (ILU) - 7 (E) Display contrast up switch not pressed 10 kΩ or higher
        4 (HDD) - 7 (E) Headup display position down switch pressed Below 1 Ω
        4 (HDD) - 7 (E) Headup display position down switch not pressed 10 kΩ or higher
        3 (HDU) - 7 (E) Headup display position up switch pressed Below 1 Ω
        3 (HDU) - 7 (E) Headup display position up switch not pressed 10 kΩ or higher
        2 (CH) - 7 (E) Headup display on switch pressed Below 1 Ω
        2 (CH) - 7 (E) Headup display on switch not pressed 10 kΩ or higher

    NG

    REPLACE SATELLITE SWITCH SET Click here

    OK

    REPLACE HEADUP DISPLAY Click here

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


    1. A019OLVE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *2

      Front view of wire harness connector

      (to Headup Display)

      Disconnect the F16 and H1 connectors.

    2. Disconnect the H1 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F16-18 (TX+) - H1-6 (TX- ) Always Below 1 Ω
      F16-18 (TX+) - Body ground Always 10 kΩ or higher
      F16-20 (CS) - H1-8 (CS) Always Below 1 Ω
      F16-20 (CS) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE HEADUP DISPLAY


    1. Replace the headup display with a new or a known good one Click here.

      OK
      The operation of the headup display returns to normal.

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

    END