Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Right Headlight ECU Malfunction (B242C,B242D)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Exterior / Lighting (ext) / Lighting System (w/ Automatic Headlight Beam Level Control System) / Right Headlight ECU Malfunction (B242C,B242D)

DESCRIPTION

The No. 1 headlight ECU sub-assembly LH stores a DTC if it detects an internal malfunction.

for Multiple Beam Headlight

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

B242C

Right Headlight ECU Malfunction
  • The engine switch is on (IG).
  • No. 1 headlight ECU sub-assembly RH internal malfunction
  • 10 seconds or more

No. 1 headlight ECU sub-assembly RH

AFS

B242D

Left Headlight ECU Malfunction
  • The engine switch is on (IG).
  • No. 1 headlight ECU sub-assembly LH internal malfunction
  • -

No. 1 headlight ECU sub-assembly LH

AFS
for Single Beam Headlight

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

B242C

Right Headlight ECU Malfunction
  • The engine switch is on (IG).
  • No. 1 headlight ECU sub-assembly RH internal malfunction
  • 10 seconds or more

No. 1 headlight ECU sub-assembly RH

HL AutoLeveling

B242D

Left Headlight ECU Malfunction
  • The engine switch is on (IG).
  • No. 1 headlight ECU sub-assembly LH internal malfunction
  • -

No. 1 headlight ECU sub-assembly LH

HL AutoLeveling

CAUTION / NOTICE / HINT

NOTICE:

  • 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.

CONFIRM MODEL

(a) Choose the model to be inspected.

Result

Proceed to

for Multiple Beam Headlight

A

for Single Beam Headlight

B
B

GO TO STEP 4

A

2.

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

3.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Wait for at least maximum 15 minutes.

(d) Turn the Techstream on.

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

(f) Check for DTCs.

Body Electrical > AFS > Trouble Codes

OK:

DTC B242C and B242D are not output.

Result

Proceed to

OK

A

NG (DTC B242C is output)

B

NG (DTC B242D is output)

C
A

USE SIMULATION METHOD TO CHECK

B

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

4.

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 / HL AutoLeveling / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > HL AutoLeveling > Clear DTCs
NEXT

5.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Wait for at least maximum 15 minutes.

(d) Turn the Techstream on.

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

(f) Check for DTCs.

Body Electrical > HL AutoLeveling > Trouble Codes

OK:

DTC B242C and B242D are not output.

Result

Proceed to

OK

A

NG (DTC B242C is output)

B

NG (DTC B242D is output)

C
A

USE SIMULATION METHOD TO CHECK

B

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

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    Open in IG Circuit (B242E)
    DESCRIPTION The No. 1 headlight ECU sub-assembly operates using the power source voltage input from the IG terminal and ECUB terminal. The IG terminal power source voltage is supplied by turning the I ...

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