METER / GAUGE SYSTEM Headup Display Malfunction

DESCRIPTION

The headup display system displays some vehicle information on the windshield glass. The headup display system consists of the combination mirror meter ECU and combination meter assembly.

The combination mirror meter ECU receives information from the combination meter assembly via communication and projects it on the windshield.

WIRING DIAGRAM

A0043Q2E03

INSPECTION PROCEDURE

Tech Tips

Before starting the following inspection, confirm the headup display (combination meter mirror ECU) position and 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

    READ VALUE USING GTS (HEAD UP DISPLAY SWITCH) Click here

    A

  2. CHECK HARNESS AND CONNECTOR (HEADUP DISPLAY CIRCUIT)


    1. A0042HAE52
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Headup Display (Combination Meter Mirror ECU))

      Disconnect the L47 combination meter mirror ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      L47-13 (12V) - Body ground Power switch on (IG) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L47-16 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HEADUP DISPLAY (COMBINATION METER MIRROR ECU) Click here

  3. READ VALUE USING GTS (HEAD UP DISPLAY SWITCH)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Combination Meter / Data List.

    5. Check the values by referring to the table below.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Head Up Display Switch (Up) Headup display position up switch/OFF or ON OFF: Headup display position up switch not pressed -
      ON: Headup display position up switch pressed -
      Head Up Display Switch (Down) Headup display position down switch/OFF or ON OFF: Headup display position down switch not pressed -
      ON: Headup display position down switch pressed -
      Head Up Display Switch (Main) Headup display main switch/OFF or ON OFF: Headup display main switch not pressed -
      ON: Headup display main switch pressed -
      OK
      Each switch condition displayed on the GTS changes with the actual switch operation.

    B

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

    A

    REPLACE NO. 3 METER CIRCUIT PLATE Click here

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


    1. Disconnect the L47 combination meter mirror ECU and L24 combination meter assembly connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L47-17 (BKR) - L24-5 (BKR) Always Below 1 Ω
      L47-17 (BKR) - Body ground Always 10 kΩ or higher
      L47-18 (LAT) - L24-6 (LAT) Always Below 1 Ω
      L47-18 (LAT) - Body ground Always 10 kΩ or higher
      L47-19 (CLKH) - L24-7 (CLKH) Always Below 1 Ω
      L47-19 (CLKH) - Body ground Always 10 kΩ or higher
      L47-20 (CLKL) - L24-8 (CLKL) Always Below 1 Ω
      L47-20 (CLKL) - Body ground Always 10 kΩ or higher
      L47-21 (SIH) - L24-9 (SIH) Always Below 1 Ω
      L47-21 (SIH) - Body ground Always 10 kΩ or higher
      L47-22 (SIL) - L24-10 (SIL) Always Below 1 Ω
      L47-22 (SIL) - Body ground Always 10 kΩ or higher
      L47-23 (WE) - L24-11 (WE) Always Below 1 Ω
      L47-23 (WE) - Body ground Always 10 kΩ or higher
      L47-2 (STP1) - L24-14 (STP1) Always Below 1 Ω
      L47-2 (STP1) - Body ground Always 10 kΩ or higher
      L47-3 (STP2) - L24-15 (STP2) Always Below 1 Ω
      L47-3 (STP2) - Body ground Always 10 kΩ or higher
      L47-4 (STP3) - L24-16 (STP3) Always Below 1 Ω
      L47-4 (STP3) - Body ground Always 10 kΩ or higher
      L47-5 (STP4) - L24-17 (STP4) Always Below 1 Ω
      L47-5 (STP4) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT SATELLITE SWITCH SET


    1. Remove the satellite switch set Click here.

      A0042VWE02

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      2 (CH) - 12 (E) HUD switch pressed Below 1 Ω
      Always 10 kΩ or higher
      14 (HDD) - 12 (E) Down switch pressed Below 1 Ω
      Always 10 kΩ or higher
      15 (HDU) - 12 (E) Up switch pressed Below 1 Ω
      Always 10 kΩ or higher
      Text in Illustration
      *A for LHD *B for RHD
      *a

      Component without harness connected

      (Satellite Switch Set)

      		 - -

    NG

    REPLACE SATELLITE SWITCH SET Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (SATELLITE SWITCH SET - COMBINATION METER ASSEMBLY)


    1. Disconnect the L50 satellite switch set and L25 combination meter assembly connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L50-12 (E) - L25-2 (E) Always Below 1 Ω
      L50-12 (E) - Body ground Always 10 kΩ or higher
      L50-15 (HDU) - L25-7 (HUDU) Always Below 1 Ω
      L50-15 (HDU) - Body ground Always 10 kΩ or higher
      L50-14 (HDD) - L25-4 (HUDD) Always Below 1 Ω
      L50-14 (HDD) - Body ground Always 10 kΩ or higher
      L50-3 (TAIL) - L25-3 (HUDI) Always Below 1 Ω
      L50-3 (TAIL) - Body ground Always 10 kΩ or higher
      L50-2 (CH) - L25-8 (HUDO) Always Below 1 Ω
      L50-2 (CH) - Body ground Always 10 kΩ or higher
      L50-6 (NVI) - L25-9 (IIND) Always Below 1 Ω
      L50-6 (NVI) - Body ground Always 10 kΩ or higher
      L50-7 (NVM) - L25-1 (NVSW) Always Below 1 Ω
      L50-7 (NVM) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. REPLACE HEADUP DISPLAY (COMBINATION METER MIRROR ECU)


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

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

    NG

    REPLACE NO. 3 METER CIRCUIT PLATE Click here

    OK

    END