Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Headlight LH Circuit (B243900,B243A00)

Toyota Corolla Cross (2022-2025) Service Manual / Vehicle Exterior / Lighting (ext) / Lighting System (w/o Afs) / Headlight LH Circuit (B243900,B243A00)

DESCRIPTION

The light control LED ECU supplies internally boosted voltage to the light control LED ECU so that the current supplied to the LED is always maintained at a constant value.

These DTCs are also output when the main body ECU (multiplex network body ECU) detects malfunctions while monitoring the applied voltage.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B243900

Headlight LH Circuit

 Detection condition:
  • Ignition switch is to ON, low beam headlights illuminated
Malfunction status:
  • Headlight unit LH malfunction
  • Headlight unit LH power source and signal malfunction
Malfunction duration:
  • 10 seconds or more
  • Headlight unit assembly LH
  • H-LP LH relay
  • Power distribution box assembly
  • Main body ECU (multiplex network body ECU)
  • Harness or connector

B243A00

Headlight RH Circuit

 Detection condition:
  • Ignition switch is to ON, low beam headlights illuminated
Malfunction status:
  • Headlight unit RH malfunction
  • Headlight unit RH power source and signal malfunction
Malfunction duration:
  • 10 seconds or more
  • Headlight unit assembly RH
  • H-LP RH relay
  • Power distribution box assembly
  • Main body ECU (multiplex network body ECU)
  • Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CAN communication malfunctions before troubleshooting this symptom.

    Click here

  • First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CXPI communication malfunctions before troubleshooting this symptom.

    Click here

PROCEDURE

1.

CLEAR DTC
Body Electrical > Main Body > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

OK:

DTC B243900 and B243A00 are not output.

Result

Proceed to

DTCs are not output

A

B243900 is output

B

B243A00 is output

C
A

USE SIMULATION METHOD TO CHECK

B

REPLACE HEADLIGHT ASSEMBLY LH

C

REPLACE HEADLIGHT ASSEMBLY RH

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