Toyota Tacoma (2015-2018) Service Manual: Problem Symptoms Table

Toyota Tacoma (2015-2018) Service Manual / Lighting / Lighting System / Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of the problem symptom. 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.
Inspect the fuses and relays related to this system before inspecting the suspected areas below.

Headlight and taillight system

Symptom	Suspected Area	See page
"Low beam" does not turn on (One side)	Headlight bulb (Low)	-
	Headlight Assembly
	Harness or connector	-
"Low beam" does not turn on (Both sides)	Low beam headlight circuit
	Harness or connector	-
	Headlight dimmer switch circuit
	Main body ECU (Multiplex network body ECU)
"High beam" does not turn on (One side)	Headlight bulb (High)	-
	Headlight Assembly
	Harness or connector	-
"High beam" does not turn on (Both sides)	High beam headlight circuit
	Harness or connector	-
	Headlight dimmer switch circuit
	Main body ECU (Multiplex network body ECU)
"Flash" does not turn on (Low beam and Hi-beam are normal)	Headlight dimmer switch circuit
"Flash" does not turn on (Low beam and Hi-beam are normal)	Main body ECU (Multiplex network body ECU)
Headlight is dark	Headlight bulb	-
Taillight does not turn on (All)	Headlight dimmer switch circuit
	Taillight relay circuit
	Main body ECU (Multiplex network body ECU)
Only one taillight turns on	Rear combination light assembly
Only one taillight turns on	Tail and stop light bulb	-
Daytime running light system does not operate (Turn signal light normal) [w/ Daytime Running Light Halogen Type]	Headlight dimmer switch circuit
	CAN communication system
	Parking brake switch assembly
	Daytime running light relay circuit
	Main body ECU (Multiplex network body ECU)
	Combination meter assembly
Daytime running light system does not operate (Turn signal light normal) [w/ Daytime Running Light LED Type]	Headlight dimmer switch circuit
	Parking brake switch assembly
	Daytime running light relay circuit
	Main body ECU (Multiplex network body ECU)

Automatic High Beam System (w/ Automatic High Beam System)

Symptom	Suspected Area	Link
Automatic high beam system does not operate or operation indicator does not illuminate.	Check automatic high beam indicator light
	Check Data List (Auto H Beam STS)
	Check Active Test (Automatic High Beam Indicator)
	Check automatic high beam main switch
	Harness or connector

Light auto turn off system

Symptom	Suspected Area	See page
Light auto turn off system does not operate	Headlight dimmer switch circuit
	Ignition switch (w/o Smart key system)	-
	Engine switch (w/ Smart key system)	-
	Door courtesy switch circuit
	Main body ECU (Multiplex network body ECU)

Front fog light system (w/ Fog Light)

Symptom	Suspected Area	See page
Front fog light does not turn on (All)	Headlight dimmer switch circuit
	Front fog light circuit
	Main body ECU (Multiplex network body ECU)
Only one front fog light does not turn on	Front fog light bulb	-

Turn signal and hazard warning system

Symptom	Suspected Area	See page
"Hazard" and "Turn" do not turn on	Combination meter assembly
"Hazard" and "Turn" do not turn on	Harness or connector	-
Hazard warning light does not turn on	Hazard warning switch circuit
	Harness or connector	-
	Combination meter assembly
Turn signal does not turn on	Meter/gauge system
	Headlight dimmer switch circuit
	Combination meter assembly

Stop light system

Symptom	Suspected Area	See page
Stop light does not operate (All)	Stop light switch assembly
	Harness or connector	-
	Rear combination light assembly
Only one stop light does not operate	Rear combination light assembly
Center stop light does not operate	Center stop light assembly
	Stop light switch assembly
	Harness or connector	-

Illuminated entry system

Symptom	Suspected Area	See page
Illuminated entry does not operate (All)	Door courtesy switch circuit
	Interior light circuit
	Main body ECU (Multiplex network body ECU)

Others

Symptom	Suspected Area	See page
1: for 2WD 2: for 4WD
Back-up light does not operate (All)	Park/neutral position switch*1
	Park/neutral position switch*2
	Harness or connector	-
	Rear combination light assembly
Only one back-up light does not operate	Rear combination light assembly
Vanity light does not operate	Vanity light
Vanity light does not operate	Harness or connector	-
Cargo light does not operate	Center stop light assembly
	Cargo light circuit
	Harness or connector	-
	Main body ECU (Multiplex network body ECU)
Room light does not operate	Roof console box assembly
Room light does not operate	Harness or connector	-

Battery saving control system

Symptom	Suspected Area	See page
Battery saving function (interior light auto cut function) does not operate	Interior light auto cut circuit
	Main body ECU (Multiplex network body ECU)
	Harness or connector	-

Dtc Check / Clear

DTC CHECK / CLEAR 1. CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the ignition switch ON. (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Main Body / Tr ...

Terminals Of Ecu

TERMINALS OF ECU 1. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Text in Illustration *1 Main Body ECU (Multiplex Network Body ECU) - - (a ...

Other materials:

Cruise Control Switch Circuit
DESCRIPTION The cruise control main switch is used to turn the dynamic radar cruise control system on and off, as well as operate 7 functions: SET, - (COAST), TAP-DOWN, RES (RESUME), + (ACCEL), TAP-UP and CANCEL. The SET, TAP-DOWN and - (COAST) functions, and the RES (RESUME), TAP-UP and + ( ...

Rear Occupant Classification Sensor RH Collision Detection (B1788)
DESCRIPTION DTC B1788 is set when the occupant detection ECU receives a collision detection signal, which is sent by the occupant classification sensor rear RH when an accident occurs. DTC B1788 is also set when the front seat with adjuster frame assembly RH is subjected to a strong impact, ...

No Response from Steering Lock ECU (B2786)
DESCRIPTION This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and steering lock ECU (steering lock actuator or upper bracket assembly) stops for 10 seconds or more. DTC No. DTC Detection Condition Trouble Area ...