Toyota Tacoma 2015-2018 Service Manual: Front Fog Light Circuit

Toyota Tacoma 2015-2018 Service Manual / Lighting / Lighting System / Front Fog Light Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the front fog lights.

WIRING DIAGRAM

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 (FRONT FOG LIGHT RELAY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to 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
Front Fog Light Relay	Front Fog Light	ON/OFF	-

OK:

Front fog lights illuminate.

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	INSPECT FOG FR RELAY

(a) Remove the FOG FR relay from the engine room relay block.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Battery voltage not applied to terminals 1 and 2	10 kΩ or higher
3 - 5	Battery voltage applied to terminals 1 and 2	Below 1 Ω

REPLACE FOG FR RELAY

3.	CHECK HARNESS AND CONNECTOR (BATTERY - FOG FR RELAY)

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

Standard Voltage:

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (FOG FR RELAY - DRIVER SIDE JUNCTION BLOCK)

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Relay terminal 2 - 1F-27	Always	Below 1 Ω
1F-27 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	INSPECT DRIVER SIDE JUNCTION BLOCK

(a) Remove the driver side junction block.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1F-27 - MB-7 (FFOG)	Always	Below 1 Ω
1F-27 - Body ground	Always	10 kΩ or higher

Text in Illustration

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

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPLACE DRIVER SIDE JUNCTION BLOCK

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