Toyota Tundra Service Manual: Taillight Circuit

Toyota Tundra Service Manual / Vehicle Interior / Lighting / Lighting System / Taillight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives headlight dimmer switch information signals and illuminates the taillights, license plate lights and front side marker lights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Using the Techstream, perform the Active Test.

Click here

Main Body

Tester Display	Test Part	Control Range	Diagnostic Note
Taillight Relay	Taillight relay (TAIL)	OFF or ON	-

OK:

Taillight relay (TAIL) operates (taillights turn on).

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	CHECK HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK ASSEMBLY - BATTERY)

(a) Disconnect the driver side junction block assembly connector.

*a	Front view of wire harness connector (to Driver Side Junction Block Assembly)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
3G-1 - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK DRIVER SIDE JUNCTION BLOCK ASSEMBLY

(a) Remove the driver side junction block assembly.

Click here

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 Voltage:

Tester Connection	Condition	Specified Condition
3H-32 - Battery negative (-) terminal	Battery voltage applied between terminals 3G-1 and A-14 (TRLY)	11 to 14 V
3H-32 - Battery negative (-) terminal	Battery voltage not applied between terminals 3G-1 and A-14 (TRLY)	Below 1 V

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY

See More:

Toyota Tundra Service Manual > Airbag System: Short in P Squib (Dual Stage - 2nd Step) Circuit (B1815-B1818)
DESCRIPTION The front passenger side squib 2nd step circuit consists of the airbag sensor assembly and instrument panel passenger without door airbag. The circuit instructs the SRS to deploy when deployment conditions are met. These DTCs are stored when a malfunction is detected in the front passeng ...

Toyota Tundra Service Manual: Taillight Circuit

System Diagram

Terminals Of Ecu

See More:

Toyota Tundra Owners Manual

Toyota Tundra Service Manual