METER / GAUGE SYSTEM Headup Display Malfunction

DESCRIPTION

This circuit is the power source circuit for the headup display (combination meter mirror ECU). 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

A01NCPQE06

INSPECTION PROCEDURE

Tech Tips

Before starting the following inspection, confirm the headup display (combination meter mirror ECU) position illuminance, then perform the on-vehicle inspection Click here.

PROCEDURE


  1. SYSTEM CHECK


    1. Check the symptom of the headup display (combination meter mirror ECU).

      Result
      Result Proceed to
      Headup display (combination meter mirror ECU) does not operate at all. A
      Cruise information display does not change. B

    B

    SYSTEM CHECK Click here

    A

  2. CHECK HARNESS AND CONNECTOR (HEADUP DISPLAY CIRCUIT)


    1. A01NI11E22
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Headup Display (Combination Meter Mirror ECU))

      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 Power switch on (IG) 11 to 14 V
      H1-2 (B) - Body ground Power switch off 11 to 14 V
      H1-3 (ACC) - Body ground Power 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.

        A01NG5OE02

      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. A01NG5OE03
        Text in Illustration
        *1

        Front view of wire harness connector

        (to Headup Display (Combination Meter Mirror ECU))
        *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.

        A01NF03E02

      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 (combination meter mirror ECU) position down switch pressed Below 1 Ω
        2 (E) - 5 (HDD) Headup display (combination meter mirror ECU) position down switch not pressed 10 kΩ or higher
        2 (E) - 6 (HDU) Headup display (combination meter mirror ECU) position up switch pressed Below 1 Ω
        2 (E) - 6 (HDU) Headup display (combination meter mirror ECU) position up switch not pressed 10 kΩ or higher
        2 (E) - 7 (CH) Headup display (combination meter mirror ECU) on switch pressed Below 1 Ω
        2 (E) - 7 (CH) Headup display (combination meter mirror ECU) on switch not pressed 10 kΩ or higher

    2. for RHD


      1. A01NF03E03
        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 (combination meter mirror ECU) position down switch pressed Below 1 Ω
        4 (HDD) - 7 (E) Headup display (combination meter mirror ECU) position down switch not pressed 10 kΩ or higher
        3 (HDU) - 7 (E) Headup display (combination meter mirror ECU) position up switch pressed Below 1 Ω
        3 (HDU) - 7 (E) Headup display (combination meter mirror ECU) position up switch not pressed 10 kΩ or higher
        2 (CH) - 7 (E) Headup display (combination meter mirror ECU) on switch pressed Below 1 Ω
        2 (CH) - 7 (E) Headup display (combination meter mirror ECU) on switch not pressed 10 kΩ or higher

    NG

    REPLACE SATELLITE SWITCH SET Click here

    OK

    REPLACE HEADUP DISPLAY (COMBINATION METER MIRROR ECU) Click here

  5. SYSTEM CHECK


    1. Confirm the symptoms.

      Result
      Result Proceed to
      All the display malfunction A
      Vehicle speed display malfunction
      Dynamic radar cruise control display malfunction
      Pre-crash safety system display malfunction
      Navigation display malfunction B

    B

    CONFIRM DTC OUTPUT Click here

    A

  6. CONFIRM DTC OUTPUT


    1. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC is output. A
      DTC is not output. B

    B

    REPLACE HEADUP DISPLAY (COMBINATION METER MIRROR ECU) Click here

    A

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


    1. A01NFT6E01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *2

      Front view of wire harness connector

      (to Headup Display (Combination Meter Mirror ECU))

      Disconnect the F16 and H1 connectors.

    2. 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

  8. REPLACE HEADUP DISPLAY (COMBINATION METER MIRROR ECU)


    1. Replace the headup display (combination meter mirror ECU) with a new or a known good one. Click here.

      OK
      The operation of the headup display (combination meter mirror ECU) returns to normal.

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

    END

  9. CONFIRM DTC OUTPUT


    1. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC is output. A
      DTC is not output. B

    B

    REPLACE COMBINATION METER ASSEMBLY Click here

    A

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


    1. A01NFT6E01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *2

      Front view of wire harness connector

      (to Headup Display (Combination Meter Mirror ECU))

      Disconnect the F16 and H1 connectors.

    2. 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

  11. REPLACE COMBINATION METER ASSEMBLY


    1. Replace the combination meter assembly to a new or a normal one Click here.

      Result
      The operation of the headup display (combination meter mirror ECU) returns to normal.

    NG

    REPLACE HEADUP DISPLAY Click here

    OK

    END

  12. REPLACE HEADUP DISPLAY


    1. Replace the headup display (combination meter mirror ECU) to a new or a normal one Click here.

      Result
      The operation of the headup display (combination meter mirror ECU) returns to normal.

    NG

    REPLACE RADIO RECEIVER ASSEMBLY

    OK

    END