Toyota Tundra Service Manual: LED Headlight LH Circuit Malfunction (B2430,B2431)

Toyota Tundra Service Manual / Vehicle Interior / Lighting / Lighting System / LED Headlight LH Circuit Malfunction (B2430,B2431)

DESCRIPTION

The illumination of the low beam headlights is controlled by the main body ECU (multiplex network body ECU). When the headlights are turned on, the main body ECU (multiplex network body ECU) receives a signal from the headlight assembly and detects the illumination condition of the low beam headlights.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
B2430	LED Headlight LH Circuit Malfunction	LED headlight LH circuit malfunction	Headlight assembly LH Main body ECU (multiplex network body ECU) Driver side junction block assembly Harness or connector
B2431	LED Headlight RH Circuit Malfunction	LED headlight RH circuit malfunction	Headlight assembly RH Main body ECU (multiplex network body ECU) Driver side junction block assembly Harness or connector

HINT:

DTC B2430 and B2431 are not output if 20 seconds have not elapsed since the ignition switch was turned on.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.	CHECK FOR DTC

(a) Clear the DTCs.

Click here

(b) Check for DTCs.

Click here

OK:

DTC B2430 and B2431 are not output.

Result	Proceed to
OK	A
NG (DTC B2430 and B2431 are output)	B
NG (DTC B2430 is output)	C
NG (DTC B2431 is output)	D

USE SIMULATION METHOD TO CHECK

GO TO STEP 6

GO TO STEP 9

2.	INSPECT HEADLIGHT RELAY (H-LP LO)

(a) Remove the headlight relay (H-LP LO) from the engine room relay block and junction block.

(b) Inspect the headlight relay (H-LP LO).

Click here

REPLACE HEADLIGHT RELAY (H-LP LO)

3.	CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP LO] - BATTERY)

(a) Remove the headlight relay (H-LP LO) from the engine room relay block and junction block.

*a	Front view of wire harness connector (to Headlight Relay [H-LP LO])

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
Headlight relay (H-LP LO) terminal 1 - Body ground	Always	11 to 14 V
Headlight relay (H-LP LO) terminal 3 - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP LO] - DRIVER SIDE JUNCTION BLOCK ASSEMBLY AND HEADLIGHT ASSEMBLY)

(a) Remove the headlight relay (H-LP LO) from the engine room relay block and junction block.

(b) Disconnect the 3H driver side junction block assembly connector.

(d) Disconnect the A58 headlight assembly RH connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Headlight relay (H-LP LO) terminal 2 - 3H-31	Always	Below 1 Ω
Headlight relay (H-LP LO) terminal 5 - A59-2 (LO)	Always	Below 1 Ω
Headlight relay (H-LP LO) terminal 2 or 3H-31 - Body ground	Always	10 kΩ or higher
Headlight relay (H-LP LO) terminal 5 or A59-2 (LO) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK DRIVER SIDE JUNCTION BLOCK ASSEMBLY

(a) Remove the driver side junction block assembly.

Click here

*a	Component without harness connected (Driver Side Junction Block Assembly)

(b) Remove the main body ECU (multiplex network body ECU) from the driver side junction block assembly.

Click here

Standard Resistance:

Tester Connection	Condition	Specified Condition
3H-31 - A-15 (HRLY)	Always	Below 1 Ω

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY

6.	CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP LO] - HEADLIGHT ASSEMBLY LH)

(a) Remove the headlight relay (H-LP LO) from the engine room relay block and junction block.

(b) Disconnect the A59 headlight assembly LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
Headlight relay (H-LP LO) terminal 5 - A59-2 (LO)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.	CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY LH - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] AND BODY GROUND)

(a) Disconnect the A59 headlight assembly LH connector.

(b) Disconnect the J165 main body ECU (multiplex network body ECU) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A59-3 (S) - J165-16 (LLEW)	Always	Below 1 Ω
A59-4 (E) - Body ground	Always	Below 1 Ω
A59-3 (S) or J165-16 (LLEW) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK HEADLIGHT ASSEMBLY LH

(a) Temporarily replace the headlight assembly LH with a new or normally functioning one.

Click here

(b) Clear the DTCs.

Click here

OK:

DTC B2430 is not output.

END (HEADLIGHT ASSEMBLY LH WAS DEFECTIVE)

MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

9.	CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP LO] - HEADLIGHT ASSEMBLY RH)

(a) Remove the headlight relay (H-LP LO) from the engine room relay block and junction block.

(b) Disconnect the A58 headlight assembly RH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
Headlight relay (H-LP LO) terminal 5 - A58-2 (LO)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

10.	CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY RH - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] AND BODY GROUND)

(a) Disconnect the A58 headlight assembly RH connector.

(b) Disconnect the J165 main body ECU (multiplex network body ECU) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A58-3 (S) - J165-3 (RLEW)	Always	Below 1 Ω
A58-4 (E) - Body ground	Always	Below 1 Ω
A58-3 (S) or J165-3 (RLEW) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.	CHECK HEADLIGHT ASSEMBLY RH

(a) Temporarily replace the headlight assembly RH with a new or normally functioning one.

Click here

(b) Clear the DTCs.

Click here

OK:

DTC B2431 is not output.

END (HEADLIGHT ASSEMBLY RH WAS DEFECTIVE)

MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

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