Lexus NX: Headlamp LH Circuit (B2439,B243A)

DESCRIPTION

This DTC is output when the headlight ECU sub-assembly receives an abnormal signal from the headlight unit.

The headlight ECU sub-assembly LH outputs DTC B2439 and B243A

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B2439

Headlamp LH Circuit

Headlight ECU sub-assembly LH light source malfunction

  • Headlight ECU sub-assembly LH
  • Headlight unit assembly LH

B243A

Headlamp RH Circuit

Headlight ECU sub-assembly RH light source malfunction

  • Headlight ECU sub-assembly RH
  • Headlight unit assembly RH

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After the headlight ECU sub-assembly LH is replaced, vehicle information registration and initialization are necessary.

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PROCEDURE

1.

CHECK FOR DTC

(a) Clear the DTCs.

Click here

Body Electrical > AFS > Clear DTCs

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

(c) Inspect the light using the dimmer switch.

(d) Check for DTCs.

Click here

Body Electrical > AFS > Trouble Codes

Result

Proceed to

DTCs B2439 and B243A are not output

A

DTC B2439 is output

B

DTC B243A is output

C

A

USE SIMULATION METHOD TO CHECK

C

GO TO STEP 3

B

2.

CHECK HEADLIGHT UNIT ASSEMBLY LH

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

Click here

(b) Clear the DTCs.

Click here

Body Electrical > AFS > Clear DTCs

(c) Check for DTCs.

Click here

Body Electrical > AFS > 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 UNIT ASSEMBLY LH

3.

CHECK HEADLIGHT UNIT ASSEMBLY RH

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

Click here

(b) Clear the DTCs.

Click here

Body Electrical > AFS > Clear DTCs

(c) Check for DTCs.

Click here

Body Electrical > AFS > 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 UNIT ASSEMBLY RH

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