LIGHTING SYSTEM, Diagnostic DTC:B2492, B2493

DTC Code DTC Name
B2492 Left Headlight Driver Module Circuit
B2493 Right Headlight Driver Module Circuit

DESCRIPTION

The headlight ECU sub-assembly sends control signals to the light control LED ECU via LIN communication and controls the additional LEDs using the drive circuit inside the light control LED ECU.

The light control LED ECU applies voltage, which is boosted inside the light control LED ECU to maintain the current applied to the additional LEDs at a constant level, to the additional LEDs and turns on/off each LED based on adaptive high beam system control.

The light control LED ECU also monitors the applied voltage value to detect current application malfunctions.

The light control LED ECU also detects malfunctions in the switching circuit that performs the adaptive high beam system illumination pattern inside the light control LED ECU.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Note
B2492 Left Headlight Driver Module Circuit

    Detection Condition:

  • Power switch is on (IG) and high beam headlight is illuminated


    Malfunction Status:

  • Adaptive high beam system circuit malfunction signals are received from light control LED ECU LH


    • Additional LED malfunction

    • Light control LED ECU LH malfunction

    • Open or short in adaptive high beam system


    Malfunction duration:

  • -

  • Headlight unit LH

  • Headlight unit assembly LH

  • Light control LED ECU LH

 Headlight ECU sub-assembly LH w/ Adaptive High Beam System
B2493 Right Headlight Driver Module Circuit

    Detection Condition:

  • Power switch is on (IG) and high beam headlight is illuminated


    Malfunction Status:

  • Adaptive high beam system circuit malfunction signals are received from light control LED ECU RH


    • Additional LED malfunction

    • Light control LED ECU RH malfunction

    • Open or short in adaptive high beam system


    Malfunction duration:

  • -

  • Headlight unit RH

  • Headlight unit assembly RH

  • Light control LED ECU RH

 Headlight ECU sub-assembly LH w/ Adaptive High Beam System

WIRING DIAGRAM


  1. for LH Side:

    B004YGGE01
    B004TDIE01
    *a Headlight Unit LH
    *b Light Control LED ECU LH
    *c Headlight Unit Assembly LH
    *d Headlight ECU Sub-assembly LH

  2. for RH Side:

    B004YGGE02
    B004TDIE02
    *a Headlight Unit RH
    *b Light Control LED ECU RH
    *c Headlight Unit Assembly RH
    *d Headlight ECU Sub-assembly RH

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > AFS > Clear DTCs

    2. Turning the power switch on (IG) and illuminating the high beam headlights using the light control switch.

    3. Check for DTCs.

      Click here


      Body Electrical > AFS > Trouble Codes
      OK
      DTC B2492 and B2493 are not output.
      Result
      Result Proceed to
      OK A
      NG (DTC B2492 is output) B
      NG (DTC B2493 is output) C

    A

    USE SIMULATION METHOD TO CHECK Click here

    C

    INSPECT HEADLIGHT UNIT ASSEMBLY RH Click here

    B

  2. INSPECT HEADLIGHT UNIT ASSEMBLY LH


    1. Remove the headlight unit LH.

      Click here

      B004WVBC01
      *a

      Component without harness connected

      (Light Control LED ECU LH)

      		 *b

      Component without harness connected

      (Headlight Unit LH)

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

      Standard Resistance
      Tester Connection Wiring Color Condition Specified Condition
      L-14 - M-21 V Always Below 1 Ω
      L-5 - M-10 W-B Always Below 1 Ω
      L-13 - M-20 O Always Below 1 Ω
      L-4 - M-9 GR Always Below 1 Ω
      L-12 - M-19 Y Always Below 1 Ω
      L-3 - M-8 R Always Below 1 Ω
      L-11 - M-18 L Always Below 1 Ω
      L-2 - M-7 W Always Below 1 Ω
      L-10 - M-6 G Always Below 1 Ω
      L-1 - M-16 W-R Always Below 1 Ω
      L-9 - M-5 B Always Below 1 Ω
      K-10 - M-15 B-W Always Below 1 Ω
      K-20 - M-4 W-L Always Below 1 Ω
      K-9 - M-14 V Always Below 1 Ω
      K-19 - M-3 W-BR Always Below 1 Ω
      K-8 - M-13 O Always Below 1 Ω
      K-18 - M-2 W-G Always Below 1 Ω
      K-7 - M-17 GR Always Below 1 Ω
      K-17 - M-11 W-R Always Below 1 Ω
      K-6 - M-22 L Always Below 1 Ω
      K-16 - N-1 W-B Always Below 1 Ω
      K-5 - N-8 BR Always Below 1 Ω
      K-15 - N-3 B-L Always Below 1 Ω
      K-4 - N-7 Y Always Below 1 Ω
      K-14 - N-6 B-R Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS) Click here

    OK

  3. INSPECT HEADLIGHT UNIT LH


    1. Remove the headlight unit LH.

      Click here

      B004U6VC01
      *1 Dry Cell Battery - -
      *a

      Component without harness connected

      (Light Control LED ECU LH)

      		 - -

    2. Set the Toyota Electrical Tester to diode check mode.

      Tech Tips

      If the tester display is below 3 V, replace the dry cell batteries inside the tester.

    3. Add 1 dry cell battery (about 1.5 V) between the Toyota Electrical Tester and inspection terminal and check if the LED illuminates.

      OK
      Tester Connection Specified Condition

      Tester positive (+) - L-14

      Tester negative (-) - L-5

      		 LED illuminates

      Tester positive (+) - L-5

      Tester negative (-) - L-13

      		 LED illuminates

      Tester positive (+) - L-13

      Tester negative (-) - L-4

      		 LED illuminates

      Tester positive (+) - L-4

      Tester negative (-) - L-12

      		 LED illuminates

      Tester positive (+) - L-12

      Tester negative (-) - L-3

      		 LED illuminates

      Tester positive (+) - L-3

      Tester negative (-) - L-11

      		 LED illuminates

      Tester positive (+) - L-11

      Tester negative (-) - L-2

      		 LED illuminates

      Tester positive (+) - L-2

      Tester negative (-) - L-10

      		 LED illuminates

      Tester positive (+) - L-10

      Tester negative (-) - L-1

      		 LED illuminates

      Tester positive (+) - L-1

      Tester negative (-) - L-9

      		 LED illuminates

      Tester positive (+) - K-10

      Tester negative (-) - K-20

      		 LED illuminates

      Tester positive (+) - K-20

      Tester negative (-) - K-9

      		 LED illuminates

      Tester positive (+) - K-9

      Tester negative (-) - K-19

      		 LED illuminates

      Tester positive (+) - K-19

      Tester negative (-) - K-8

      		 LED illuminates

      Tester positive (+) - K-8

      Tester negative (-) - K-18

      		 LED illuminates

      Tester positive (+) - K-18

      Tester negative (-) - K-7

      		 LED illuminates

      Tester positive (+) - K-7

      Tester negative (-) - K-11

      		 LED illuminates

      Tester positive (+) - K-17

      Tester negative (-) - K-6

      		 LED illuminates

      Tester positive (+) - K-6

      Tester negative (-) - K-16

      		 LED illuminates

      Tester positive (+) - K-16

      Tester negative (-) - K-5

      		 LED illuminates

      Tester positive (+) - K-5

      Tester negative (-) - K-15

      		 LED illuminates

      Tester positive (+) - K-15

      Tester negative (-) - K-4

      		 LED illuminates

      Tester positive (+) - K-4

      Tester negative (-) - K-14

      		 LED illuminates
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE LIGHT CONTROL LED ECU LH Click here

    NG

    REPLACE HEADLIGHT UNIT LH Click here

  4. INSPECT HEADLIGHT UNIT ASSEMBLY RH


    1. Remove the headlight unit RH.

      Click here

      B004WVBC01
      *a

      Component without harness connected

      (Light Control LED ECU RH)

      		 *b

      Component without harness connected

      (Headlight Unit RH)

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

      Standard Resistance
      Tester Connection Wiring Color Condition Specified Condition
      L-14 - M-21 V Always Below 1 Ω
      L-5 - M-10 W-B Always Below 1 Ω
      L-13 - M-20 O Always Below 1 Ω
      L-4 - M-9 GR Always Below 1 Ω
      L-12 - M-19 Y Always Below 1 Ω
      L-3 - M-8 R Always Below 1 Ω
      L-11 - M-18 L Always Below 1 Ω
      L-2 - M-7 W Always Below 1 Ω
      L-10 - M-17 G Always Below 1 Ω
      L-1 - M-16 W-R Always Below 1 Ω
      L-9 - M-5 B Always Below 1 Ω
      K-10 - M-15 B-W Always Below 1 Ω
      K-20 - M-4 W-L Always Below 1 Ω
      K-9 - M-14 V Always Below 1 Ω
      K-19 - M-3 W-BR Always Below 1 Ω
      K-8 - M-13 O Always Below 1 Ω
      K-18 - M-2 W-G Always Below 1 Ω
      K-7 - N-4 GR Always Below 1 Ω
      K-17 - N-8 W-R Always Below 1 Ω
      K-6 - N-3 L Always Below 1 Ω
      K-16 - N-10 W-B Always Below 1 Ω
      K-5 - M-1 BR Always Below 1 Ω
      K-15 - M-12 B-L Always Below 1 Ω
      K-4 - M-11 Y Always Below 1 Ω
      K-14 - M-22 B-R Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS) Click here

    OK

  5. INSPECT HEADLIGHT UNIT RH


    1. Remove the headlight unit RH.

      Click here

      B004U6VC01
      *1 Dry Cell Battery - -
      *a

      Component without harness connected

      (Light Control LED ECU RH)

      		 - -

    2. Set the Toyota Electrical Tester to diode check mode.

      Tech Tips

      If the tester display is below 3 V, replace the dry cell batteries inside the tester.

    3. Add 1 dry cell battery (about 1.5 V) between the Toyota Electrical Tester and inspection terminal and check if the LED illuminates.

      OK
      Tester Connection Specified Condition

      Tester positive (+) - L-14

      Tester negative (-) - L-5

      		 LED illuminates

      Tester positive (+) - L-5

      Tester negative (-) - L-13

      		 LED illuminates

      Tester positive (+) - L-13

      Tester negative (-) - L-4

      		 LED illuminates

      Tester positive (+) - L-4

      Tester negative (-) - L-12

      		 LED illuminates

      Tester positive (+) - L-12

      Tester negative (-) - L-3

      		 LED illuminates

      Tester positive (+) - L-3

      Tester negative (-) - L-11

      		 LED illuminates

      Tester positive (+) - L-11

      Tester negative (-) - L-2

      		 LED illuminates

      Tester positive (+) - L-2

      Tester negative (-) - L-10

      		 LED illuminates

      Tester positive (+) - L-10

      Tester negative (-) - L-1

      		 LED illuminates

      Tester positive (+) - L-1

      Tester negative (-) - L-9

      		 LED illuminates

      Tester positive (+) - K-10

      Tester negative (-) - K-20

      		 LED illuminates

      Tester positive (+) - K-20

      Tester negative (-) - K-9

      		 LED illuminates

      Tester positive (+) - K-9

      Tester negative (-) - K-19

      		 LED illuminates

      Tester positive (+) - K-19

      Tester negative (-) - K-8

      		 LED illuminates

      Tester positive (+) - K-8

      Tester negative (-) - K-18

      		 LED illuminates

      Tester positive (+) - K-18

      Tester negative (-) - K-7

      		 LED illuminates

      Tester positive (+) - K-7

      Tester negative (-) - K-11

      		 LED illuminates

      Tester positive (+) - K-17

      Tester negative (-) - K-6

      		 LED illuminates

      Tester positive (+) - K-6

      Tester negative (-) - K-16

      		 LED illuminates

      Tester positive (+) - K-16

      Tester negative (-) - K-5

      		 LED illuminates

      Tester positive (+) - K-5

      Tester negative (-) - K-15

      		 LED illuminates

      Tester positive (+) - K-15

      Tester negative (-) - K-4

      		 LED illuminates

      Tester positive (+) - K-4

      Tester negative (-) - K-14

      		 LED illuminates
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE LIGHT CONTROL LED ECU RH Click here

    NG

    REPLACE HEADLIGHT UNIT RH Click here