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Home >> Lexus >> 2021 >> GX 460 Base >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge / Display System (Diagnostic Codes & Symptom Tests) >> Meter / Gauge System >> Meter Illumination is Always Dark [08/2015 - 08/2019] >> Procedure

Meter Illumination is Always Dark [08/2015 - 08/2019]: Procedure

  1. CHECK CAN COMMUNICATION SYSTEM 
    1. Check if a CAN communication DTC is output (Refer to DIAGNOSIS SYSTEM [08/2015 - 08/2019] ).
      RESULT

      Result Proceed to
      CAN communication DTC is not output A
      CAN communication DTC is output B

    Result: 

    GO TO CAN COMMUNICATION SYSTEM 

    (Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

    Result: 

    See step  2

  2. CHECK DTC (LIGHT SENSOR CIRCUIT) 
    1. Check if DTC B1244 is output (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).
      RESULT

      Result Proceed to
      DTC B1244 is not output A
      DTC B1244 is output B

    Result: 

    GO TO LIGHTING SYSTEM 

    (Refer to DTC B1244: Light Sensor Circuit Malfunction [08/2015 - 08/2019] )

    Result: 

    See step  3

  3. CHECK OPERATION (HEATER CONTROL PANEL) 
    1. Turn the engine switch on (IG).
    2. Turn the light control switch to the tail, head, or AUTO position.
    3. Cover the automatic light control sensor.
    4. Check the heater control panel illumination.
      RESULT

      Result Proceed to
      Heater control panel illumination does not operate normally A
      Heater control panel illumination operates normally B

      HINT: 

      Both the heater control panel and the combination meter assembly illumination dim according to the dimmer signal. Therefore, when only the meter illumination is always dark, there may be a malfunction in the combination meter assembly.

    Result: 

    REPLACE COMBINATION METER ASSEMBLY 

    (Refer to REMOVAL [08/2015 - 08/2019] )

    Result: 

    See step  4

  4. CHECK OPERATION (AUTOMATIC LIGHT CONTROL SYSTEM) 
    1. Turn the engine switch on (IG).
    2. Turn the light control switch to the AUTO position.
    3. Cover the automatic light control sensor.
    4. Check the taillights and low beam headlights.

      OK

      The taillights and low beam headlights come on.

    5. Uncover the automatic light control sensor.
    6. Check the low beam headlights and taillights.

      OK

      The taillights and low beam headlights go off.

      RESULT

      Result Proceed to
      Automatic light control system operates normally A
      Automatic light control system does not operate normally B

    Result: 

    CHECK LIGHTING SYSTEM 

    (Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

    Result: 

    See step  5

  5. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 
    1. Replace the main body ECU (multiplex network body ECU) with a new or normally functioning one (Refer to REMOVAL [08/2015 - 08/2019] ).
    2. Check the operation of the combination meter assembly.

      OK

      The operation of the combination meter assembly returns to normal.

      HINT: 

      The combination meter assembly controls the meter illumination based on an auto dimmer signal from the main body ECU (multiplex network body ECU). When the meter illumination is always dark (very dim), it may be due to the main body ECU (multiplex network body ECU) sending an auto dimmer signal to the combination meter assembly because of a malfunction in the main body ECU (multiplex network body ECU).

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE COMBINATION METER ASSEMBLY 

    (Refer to REMOVAL [08/2015 - 08/2019] )