Toyota Tacoma manuals

Toyota Tacoma (2015-2018) Service Manual: High Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the high beam headlights.

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 (HEAD LIGHT Hi)

(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

Head Light Hi

High beam headlights

ON/OFF

-

OK:

High beam headlights illuminate.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT DIMMER RELAY

(a) Remove the headlight dimmer 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

Voltage is not applied between terminals 1 and 2

10 kΩ or higher

3 - 5

Voltage is applied between terminals 1 and 2

Below 1 Ω

NG

REPLACE DIMMER RELAY

OK

3.

CHECK HARNESS AND CONNECTOR (BATTERY - DIMMER RELAY)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

Relay terminal 2 - Body ground

Always

11 to 14 V

Relay terminal 5 - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK HARNESS AND CONNECTOR (DIMMER RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

(a) Disconnect the M6 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Relay terminal 1 - M6-1 (DIM)

Always

Below 1 Ω

M6-1 (DIM) - Body ground

Always

10 kΩ or higher

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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