Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000ZY86
Model Year Start: 2017 Model: Sienna Prod Date Range: [08/2016 -           ]
Title: LIGHTING (EXT): LIGHTING SYSTEM: Taillight Relay Circuit; 2017 - 2020 MY Sienna [08/2016 -        ]

Taillight Relay Circuit

DESCRIPTION

The main body ECU controls the operation of the TAIL relay.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

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) Check that the relay operates.

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

(See page 2017 MY Sienna [08/2016 - 11/2017]; LIGHTING (EXT): LIGHTING SYSTEM: PROBLEM SYMPTOMS TABLE 2018 - 2020 MY Sienna [11/2017 -        ]; LIGHTING (EXT): LIGHTING SYSTEM: PROBLEM SYMPTOMS TABLE )

NG

2.

CHECK HARNESS AND CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the instrument panel junction block assembly connector.

*a

Front view of wire harness connector

(to Instrument Panel Junction Block Assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

2K-1 - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Temporarily replace the instrument panel junction block assembly with a new or normally functioning one.

NEXT

4.

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) Check that the relay operates.

Main Body

Tester Display

Test Part

Control Range

Diagnostic Note

Taillight Relay

Taillight relay

ON/OFF

-

OK:

Taillight relay operates. (Taillights illuminate.)

OK

END (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE)

NG

REPLACE MAIN BODY ECU