Toyota Tacoma (2015-2018) Service Manual: Horn System

Toyota Tacoma (2015-2018) Service Manual / Horn / Horn System

Parts Location

PARTS LOCATION

ILLUSTRATION

Precaution

PRECAUTION

1. IGNITION SWITCH EXPRESSIONS

(a) The type of ignition switch used on this model differs depending on the specifications of the vehicle. The expressions listed in the table below are used in this section.

Expression	Ignition Switch (Position)	Engine Switch (Condition)
Ignition Switch off	LOCK	Off (Lock)
Ignition Switch ACC	ACC	On (ACC)
Ignition Switch ON	ON	On (IG)
Engine Start	START	Start

System Diagram

SYSTEM DIAGRAM

Data List / Active Test

DATA LIST / ACTIVE TEST

1. PERFORM ACTIVE TEST

HINT:

Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

(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
Vehicle Horn	Vehicle horns	ON/OFF	-

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

HORN SYSTEM

Symptom	Suspected Area	See page
Horn does not sound	HORN fuse	-
	HORN relay
	Horn button assembly	-
	Steering pad switch assembly
	Spiral cable with sensor sub-assembly
	Driver side junction block	-
	Harness or connector	-
Horn blows all the time	HORN relay
	Horn button assembly	-
	Steering pad switch assembly
	Spiral cable with sensor sub-assembly
	Driver side junction block	-
	Main body ECU (Multiplex network body ECU)	-
	Harness or connector	-

Horn Relay

On-vehicle Inspection ON-VEHICLE INSPECTION PROCEDURE 1. INSPECT HORN RELAY ASSEMBLY (a) Check the resistance. (1) Measure the resistance according to the value(s) in the table below ...

Low Pitched Horn

Components COMPONENTS ILLUSTRATION Inspection INSPECTION PROCEDURE 1. INSPECT LOW PITCHED HORN ASSEMBLY (a) Check the operation. (1) Apply battery voltage to the terminal 1 an ...

Other materials:

Diagnosis System
DIAGNOSIS SYSTEM 1. CHECK DLC3 (a) The vehicle ECUs use ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-3 and matches the ISO 15765-4 format. Terminals No. (Symbols) Terminal Description Condition Spe ...

Precaution
PRECAUTION 1. IGNITION SWITCH EXPRESSION (a) The type of ignition switch used on this model differs depending on the specifications of the vehicle. The expressions listed in the table below are used in this section. Expression Ignition Switch (Position) Engine S ...

Open Circuit in IG1/IG2 Power Source Circuit (C1242)
DESCRIPTION If there is a problem with the skid control ECU (master cylinder solenoid) power supply circuit, the skid control ECU outputs the DTC and prohibits operation under the fail safe function. If the voltage supplied to terminal IG1 and/or IG2 is not within the DTC detection threshold ...