Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000025DLO
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [09/2022 - 11/2022]
Title: LIGHTING (EXT): LIGHTING SYSTEM (for TMC Made): B243900,B243A00; Headlight LH Circuit; 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]

DTC

B243900

Headlight LH Circuit

DTC

B243A00

Headlight RH Circuit

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

DTC Output from

B243900

Headlight LH Circuit

Detection condition:

  • All of the following conditions are met:
    • Ignition switch ON
    • Low beam headlights on

Malfunction status:

  • Headlight unit assembly malfunction
  • Open/short in headlight LH circuit

Malfunction duration:

  • 10 seconds or more
  • Headlight assembly LH
  • Main body ECU (multiplex network body ECU)

Main Body

B243A00

Headlight RH Circuit

Detection condition:

  • All of the following conditions are met:
    • Ignition switch ON
    • Low beam headlights on

Malfunction status:

  • Headlight unit assembly malfunction
  • Open/short in headlight RH circuit

Malfunction duration:

  • 10 seconds or more
  • Headlight assembly RH
  • Main body ECU (multiplex network body ECU)

Main Body

WIRING DIAGRAM

for G16E-GTS

for M20A-FKS, 2ZR-FXE

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    for HV Model: Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION

    for Gasoline Model: Click here 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022 - 11/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function (Gasoline Model, except TMMMS Made)): REGISTRATION

  • 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 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; NETWORKING: CXPI COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

NEXT

2.

CHECK FOR DTC

(a) Turn the ignition switch to ON.

(b) Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.

(c) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

OK:

DTC B243900 and B243A00 are not output.

Result

Proceed to

OK

A

NG (DTC B243900 is output)

B

NG (DTC B243A00 is output)

C
A

USE SIMULATION METHOD TO CHECK

C

GO TO STEP 6

B

3.

CHECK HEADLIGHT ASSEMBLY LH

(a) Interchange the headlight assembly LH with RH and connect the connectors.

Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; LIGHTING (EXT): HEADLIGHT ASSEMBLY: DISASSEMBLY

NEXT

4.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

NEXT

5.

CHECK FOR DTC

(a) Turn the ignition switch to ON.

(b) Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.

(c) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

Result

Proceed to

DTC B243900 is output

A

DTC B243A00 is output

B
A

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

B

REPLACE HEADLIGHT ASSEMBLY LH

6.

CHECK HEADLIGHT ASSEMBLY RH

(a) Interchange the headlight assembly RH with LH and connect the connectors.

Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; LIGHTING (EXT): HEADLIGHT ASSEMBLY: DISASSEMBLY

NEXT

7.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

NEXT

8.

CHECK FOR DTC

(a) Turn the ignition switch to ON.

(b) Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.

(c) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

Result

Proceed to

DTC B243A00 is output

A

DTC B243900 is output

B
A

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

B

REPLACE HEADLIGHT ASSEMBLY RH