Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Headlight LH Circuit (B2439,B243A)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Exterior / Lighting (ext) / Lighting System(for Hv Model With Cornering Light) / Headlight LH Circuit (B2439,B243A)

DESCRIPTION

The headlight ECU sub-assembly LH and headlight ECU sub-assembly RH internally boost the power supply voltage to ensure a constant supplied current for the low beam LED of their respective headlight.

By monitoring the LED power supply voltage, abnormal current and malfunctions can be detected.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

B2439

Headlight LH Circuit
  • All of the following conditions are met:
    • Power switch on (IG)
    • Low beam headlights on
Malfunction status:
  • Headlight assembly malfunction
  • Open/short in low beam circuit
  • 10 seconds or more
  • Headlight ECU sub-assembly LH
  • Headlight assembly LH

Headlight ECU sub-assembly LH

B243A

Headlight RH Circuit
  • All of the following conditions are met:
    • Power switch on (IG)
    • Low beam headlights on
Malfunction status:
  • Headlight assembly malfunction
  • Open/short in low beam circuit
  • 10 seconds or more
  • Headlight ECU sub-assembly RH
  • Headlight assembly RH

Headlight ECU sub-assembly RH

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information the headlight ECU sub-assembly LH.

    Click here

  • If the headlight assembly LH has been replaced, it is necessary to synchronize the vehicle information the headlight ECU sub-assembly LH.

    Click here

PROCEDURE

1.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > HL AutoLeveling > Clear DTCs Body Electrical > HL AutoLeveling (Sub) > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

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

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(f) Check for DTCs.

Body Electrical > HL AutoLeveling > Trouble Codes Body Electrical > HL AutoLeveling (Sub) > Trouble Codes

OK:

DTC B2439 and B243A are not output.

Result

Proceed to

OK

A

NG (DTC B2439 is output)

B

NG (DTC B243A is output)

C
A

USE SIMULATION METHOD TO CHECK

C

GO TO STEP 6

B

3.

CHECK HEADLIGHT ASSEMBLY LH

(a) Remove each headlight ECU sub-assembly, interchange the headlight assembly LH with RH and connect the connectors.

Click here

NEXT

4.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > HL AutoLeveling > Clear DTCs Body Electrical > HL AutoLeveling (Sub) > Clear DTCs
NEXT

5.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

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

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(f) Check for DTCs.

Body Electrical > HL AutoLeveling > Trouble Codes Body Electrical > HL AutoLeveling (Sub) > Trouble Codes

Result

Proceed to

DTC B2439 is output

A

DTC B243A is output

B
A

REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH

B

REPLACE HEADLIGHT ASSEMBLY LH

6.

CHECK HEADLIGHT ASSEMBLY RH

(a) Remove each headlight ECU sub-assembly, interchange the headlight assembly RH with LH and connect the connectors.

Click here

NEXT

7.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > HL AutoLeveling > Clear DTCs Body Electrical > HL AutoLeveling (Sub) > Clear DTCs
NEXT

8.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

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

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.

(f) Check for DTCs.

Body Electrical > HL AutoLeveling > Trouble Codes Body Electrical > HL AutoLeveling (Sub) > Trouble Codes

Result

Proceed to

DTC B243A is output

A

DTC B2439 is output

B
A

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH

B

REPLACE HEADLIGHT ASSEMBLY RH

    Vehicle Speed Sensor (B2415)

    Variation Code not Written (B2451)

    See More:

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Sfi System: Lost Communication with Active Grille Air Shutter Module "A" Missing Message (U028487)
    MONITOR DESCRIPTION The ECM and swing grille actuator assembly (active grille air shutter ECU) send and receive signals via CAN communication. If a communication error occurs between the ECM and swing grille actuator assembly, the ECM stores this DTC. DTC No. Detection Item DTC Detection Condition T ...

    Toyota Avalon (XX50) 2019-2022 Owners Manual

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

    © 2025 Copyright www.tavalon.net
    0.0164