Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Left Headlight ECU Variation Error (B2456)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Vehicle Exterior / Lighting (ext) / Lighting System (w/ Automatic Headlight Beam Level Control System) / Left Headlight ECU Variation Error (B2456)

DESCRIPTION

This DTC is stored if the No. 1 headlight ECU sub-assembly LH for another destination is installed.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

B2456

Left Headlight ECU Variation Error
  • The engine switch is on (IG).
  • Vehicle specification information received via CAN communication is continuously mismatched
  • -
  • ECM
  • Main body ECU (multiplex network body ECU)
  • No. 1 headlight ECU sub-assembly LH

AFS

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

  • Before replacing the ECM, refer to Registration.

    Click here

  • If the No. 1 headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the No. 1 headlight ECU sub-assembly LH.

    Click here

  • If the headlight assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the No. 1 headlight ECU sub-assembly LH.*

    Click here

  • When replacing the No. 1 headlight ECU sub-assembly LH, always replace it with a new one. If a No. 1 headlight ECU sub-assembly LH which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.
  • When replacing the headlight assembly LH, always replace it with a new one. If a headlight assembly LH which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.*
    • *: for TMMC Made

PROCEDURE

1.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / AFS / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > AFS > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / AFS / Trouble Codes.

(e) Check for DTCs.

Body Electrical > AFS > Trouble Codes

OK:

DTC B2456 is not output.

OK

USE SIMULATION METHOD TO CHECK

NG

3.

CHECK ECM

(a) Check if the part number of the ECM installed to the vehicle is correct.

OK:

Part number is correct.

NG

REPLACE ECM

OK

4.

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

(a) Check if the part number of the main body ECU (multiplex network body ECU) installed to the vehicle is correct.

OK:

Part number is correct.

OK

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    Abnormal Height Sensor Data at Initialization (B2452)
    DESCRIPTION The No. 1 headlight ECU sub-assembly LH stores this DTC if the value from the rear height control sensor sub-assembly RH is out of range when performing initialization of the No. 1 headlig ...

    Control Module Communication Bus Off (U0073,U0100,U0101,U0126,U0129,U0142,U0155)
    DESCRIPTION These DTCs are stored if a CAN communication malfunction occurs between the No. 1 headlight ECU sub-assembly LH and other ECUs. DTC No. Detection Item DTC Detection Condition Trou ...

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