Toyota Tacoma manuals

Toyota Tacoma (2015-2018) Service Manual: Taillight Relay Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the operation of the TAIL relay.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.
  • If the main body ECU (multiplex network body ECU) is replaced, refer to Registration (See page ).*1
    • *1: w/ Smart Key System

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (TAILLIGHT RELAY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Main Body

Tester Display

Test Part

Control Range

Diagnostic Note

Taillight Relay

Taillight relay

ON/OFF

-

OK:

Taillight relay operates. (Taillights illuminate.)

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

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

(a) Disconnect the 1K driver side junction block connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

1K-1 - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

INSPECT DRIVER SIDE JUNCTION BLOCK

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

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

Text in Illustration

*a

Component without harness connected

(Driver Side Junction Block)

-

-

(c) Connect a positive (+) lead from the battery to terminal 1K-1.

(d) Connect a negative (-) lead from the battery to terminal MB-14 (TRLY).

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

1F-3 - Battery negative terminal

Always

11 to 14 V

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE DRIVER SIDE JUNCTION BLOCK

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