Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Headlight Beam Level Control Motor LH Lost Communication (B2424,B2425)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Exterior / Lighting (ext) / Lighting System (w/ Automatic Headlight Beam Level Control System) / Headlight Beam Level Control Motor LH Lost Communication (B2424,B2425)

DESCRIPTION

Each No. 1 headlight ECU sub-assembly and headlight leveling motor communicate via LIN communication.

The headlight leveling motor operates according to power supplied and automatic headlight beam level control signals from its respective No. 1 headlight ECU sub-assembly and sends its operating state to the No. 1 headlight ECU sub-assembly.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

B2424

Headlight Beam Level Control Motor LH Lost Communication
  • The engine switch is on (IG).
  • LIN communication error
  • 10 seconds or more
  • Headlight unit LH
  • Headlight unit RH
  • Harness or connector
  • No. 1 headlight ECU sub-assembly LH
  • No. 1 headlight ECU sub-assembly RH

AFS

B2425

Headlight Beam Level Control Motor RH Lost Communication
  • The engine switch is on (IG).
  • LIN communication error
  • 10 seconds or more
  • Headlight unit RH
  • Headlight unit LH
  • Harness or connector
  • No. 1 headlight ECU sub-assembly RH
  • No. 1 headlight ECU sub-assembly LH

AFS

WIRING DIAGRAM

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.

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) Wait 10 seconds or more.

(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 B2424 and B2425 are not output.

Result

Proceed to

OK

A

NG (DTC B2424 is output)

B

NG (DTC B2425 is output)

C

NG (DTC B2424 and B2425 are output)

D
A

USE SIMULATION METHOD TO CHECK

C

GO TO STEP 4

D

GO TO STEP 7

B

3.

INSPECT NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

*a

Component without harness connected

(No. 1 Headlight ECU Sub-assembly LH)

-

-

(a) Remove the No. 1 headlight ECU sub-assembly LH.

Click here

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A49-20 (LINL) - C-13 (LINLI)

Always

Below 1 Ω

Result

Proceed to

OK (for TMC Made)

A

OK (for TMMC Made)

B

NG

C
A

REPLACE HEADLIGHT UNIT LH

B

REPLACE HEADLIGHT ASSEMBLY LH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

4.

CHECK HARNESS AND CONNECTOR (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH - NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH)

(a) Disconnect the A49 No. 1 headlight ECU sub-assembly LH connector.

(b) Disconnect the A50 No. 1 headlight ECU sub-assembly RH connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A49-20 (LINL) - A50-20 (LINL)

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH (LINL TERMINAL SIGNAL OUTPUT)

*a

Front view of wire harness connector

(to No. 1 Headlight ECU Sub-assembly RH)

(a) Connect the A49 No. 1 headlight ECU sub-assembly LH connector.

(b) Using a Techstream, check the waveform.

OK:

Tester Connection

Condition

Specified Condition

A50-20 (LINL) - Body ground

Engine switch on (IG)

Pulse generation
NG

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

OK

6.

INSPECT NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

*a

Component without harness connected

(No. 1 Headlight ECU Sub-assembly RH)

-

-

(a) Remove the No. 1 headlight ECU sub-assembly RH.

Click here

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A50-20 (LINL) - C-13 (LINLI)

Always

Below 1 Ω

Result

Proceed to

OK (for TMC Made)

A

OK (for TMMC Made)

B

NG

C
A

REPLACE HEADLIGHT UNIT RH

B

REPLACE HEADLIGHT ASSEMBLY RH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

7.

CHECK HARNESS AND CONNECTOR (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH - NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH)

(a) Disconnect the A49 No. 1 headlight ECU sub-assembly LH connector.

(b) Disconnect the A50 No. 1 headlight ECU sub-assembly RH connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A49-20 (LINL) or A50-20 (LINL) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

CLEAR DTC

(a) Connect the A49 No. 1 headlight ECU sub-assembly LH connector.

(b) Connect the Techstream to the DLC3.

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

(d) Turn the Techstream on.

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

(f) Clear the DTCs.

Body Electrical > AFS > Clear DTCs
NEXT

9.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Wait 10 seconds or more.

(d) Turn the Techstream on.

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

(f) Check for DTCs.

Body Electrical > AFS > Trouble Codes

Result

Proceed to

DTC B2425 is output

A

DTC B2424 and B2425 are output

B
B

GO TO STEP 13

A

10.

CHECK NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

(a) Remove the No. 1 headlight ECU sub-assembly RH.

Click here

(b) Connect the A50 No. 1 headlight ECU sub-assembly RH connector.

NEXT

11.

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

12.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Wait 10 seconds or more.

(d) Turn the Techstream on.

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

(f) Check for DTCs.

Body Electrical > AFS > Trouble Codes

Result

Proceed to

DTC B2425 is output (for TMC Made)

A

DTC B2425 is output (for TMMC Made)

B

DTC B2424 and B2425 are output

C
A

REPLACE HEADLIGHT UNIT RH

B

REPLACE HEADLIGHT ASSEMBLY RH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH

13.

CHECK NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

(a) Remove the No. 1 headlight ECU sub-assembly LH.

Click here

(b) Connect the A49 No. 1 headlight ECU sub-assembly LH connector.

(c) Connect the A50 No. 1 headlight ECU sub-assembly RH connector.

NEXT

14.

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

15.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Wait 10 seconds or more.

(d) Turn the Techstream on.

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

(f) Check for DTCs.

Body Electrical > AFS > Trouble Codes

Result

Proceed to

DTC B2424 is output (for TMC Made)

A

DTC B2424 is output (for TMMC Made)

B

DTC B2424 and B2425 are output

C
A

REPLACE HEADLIGHT UNIT LH

B

REPLACE HEADLIGHT ASSEMBLY LH

C

REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH

    Height Control Sensor (B2416,B241A)
    DESCRIPTION The No. 1 headlight ECU sub-assembly LH determines the vehicle height and performs automatic headlight beam level control based on signals from the rear height control sensor sub-assembly ...

    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 ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Vehicle Stability Control System: Left Rear Wheel Speed Sensor Circuit Intermittent (C050C1F)
    DESCRIPTION The speed sensor detects wheel speed and sends the appropriate signals to the skid control ECU (brake actuator assembly). These signals are used for brake control. Speed sensor rotors have rows of alternating N and S magnetic poles, and their magnetic fields change when the rotors turn. ...

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Rear Differential Carrier Assembly: Removal
    REMOVAL CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization, or registration) that must be performed after parts are removed and installed, or replaced during rear differential carrier assembly with differential support removal/installation are shown below. Nece ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2025 Copyright www.lexusrx.net
    0.0196