Toyota Corolla Cross: Headlight Source LH Malfunction (B243900,B243A00)

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 Lo/Hi 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
B243900	Headlight Source LH Malfunction	Detection condition: All of the following conditions are met: Ignition switch ON Low beam headlights on Malfunction status: Headlight assembly malfunction Open/short in Lo/Hi beam circuit Malfunction duration: 10 seconds or more	Headlight unit assembly LH Headlight ECU sub-assembly LH
B243A00	Headlight Source RH Malfunction	Detection condition: All of the following conditions are met: Ignition switch ON Low beam headlights on Malfunction status: Headlight assembly malfunction Open/short in Lo/Hi beam circuit Malfunction duration: 10 seconds or more	Headlight unit 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 and initialize the headlight ECU sub-assembly LH.

Click here

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Headlight Control > Clear DTCs Body Electrical > Headlight Control (Sub) > Clear DTCs

NEXT

2.	CHECK FOR DTC

(a) Turn the ignition switch to ON.

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

(c) Check for DTCs.

Body Electrical > Headlight Control > Trouble Codes Body Electrical > Headlight Control (Sub) > Trouble Codes

OK:

DTC B243900 and B243A00 are not output.

Result	Proceed to
DTCs are not output	A
B243900 is output	B
DTC B243A00 is output	C

A

USE SIMULATION METHOD TO CHECK

C

GO TO STEP 6

B

3.	CHECK HEADLIGHT UNIT ASSEMBLY LH

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

Click here

NEXT

4.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Headlight Control > Clear DTCs Body Electrical > Headlight Control (Sub) > Clear DTCs

NEXT

5.	CHECK FOR DTC

(a) Turn the ignition switch to ON.

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

(c) Check for DTCs.

Body Electrical > Headlight Control > Trouble Codes Body Electrical > Headlight Control (Sub) > Trouble Codes

Result	Proceed to
B243900 is output	A
B243A00 is output	B

A

REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH

B

REPLACE HEADLIGHT UNIT ASSEMBLY LH

6.	CHECK HEADLIGHT UNIT ASSEMBLY RH

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

Click here

NEXT

7.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Headlight Control > Clear DTCs Body Electrical > Headlight Control (Sub) > Clear DTCs

NEXT

8.	CHECK FOR DTC

(a) Turn the ignition switch to ON.

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

(c) Check for DTCs.

Body Electrical > Headlight Control > Trouble Codes Body Electrical > Headlight Control (Sub) > Trouble Codes

Result	Proceed to
B243A00 is output	A
B243900 is output	B

A

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH

B

REPLACE HEADLIGHT UNIT ASSEMBLY RH

READ NEXT: