Toyota Corolla Cross: Taillight Relay Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the operation of the TAIL relay.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

• Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
• First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CXPI communication malfunctions before troubleshooting this symptom.

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PROCEDURE

1.	READ VALUE USING GTS

(a) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Input Signal	Tail light input	OFF or ON	OFF: Taillight is not input ON: Tail light is input	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Input Signal

OK:

Display changes according to the taillight illumination condition.

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

OK

2.	READ VALUE USING GTS

(a) Turn the light control switch to the TAIL position.

(b) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

NG

GO TO STEP 4

OK

3.	READ VALUE USING GTS

(a) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Output Signal	Tail light output	OFF or ON	OFF: Taillight is not output ON: Tail light is output	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Output Signal

OK:

Display changes according to the taillight illumination condition.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

4.	INSPECT REAR COMBINATION LIGHT ASSEMBLY LH

(a) Disconnect the S14 rear combination light assembly LH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE REAR COMBINATION LIGHT ASSEMBLY LH

NG

5.	INSPECT REAR COMBINATION LIGHT ASSEMBLY RH

(a) Disconnect the S15 rear combination light assembly RH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE REAR COMBINATION LIGHT ASSEMBLY RH

NG

6.	INSPECT REAR LIGHT ASSEMBLY LH

(a) Disconnect the U44 rear light assembly LH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE REAR LIGHT ASSEMBLY LH

NG

7.	INSPECT REAR LIGHT ASSEMBLY RH

(a) Disconnect the U43 rear light assembly RH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE REAR LIGHT ASSEMBLY RH

NG

8.	INSPECT LICENSE PLATE LIGHT ASSEMBLY LH

(a) Disconnect the U2 license plate light assembly LH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE LICENSE PLATE LIGHT ASSEMBLY LH

NG

9.	INSPECT LICENSE PLATE LIGHT ASSEMBLY RH

(a) Disconnect the U3 license plate light assembly RH connector.

(b) Turn the light control switch to the AUTO (OFF) position.

NOTICE:

If the low beam headlights or clearance lights illuminate when the ignition switch is turned ON, shine a light on the automatic light control sensor to turn the low beam headlights off before operating the headlight dimmer switch.

(c) Turn the light control switch to the TAIL position.

(d) Using the GTS, read the Data List.

Body Electrical > Power Distribution Box > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Tail Light Fuse Shut Off Status	Tail light fuse condition	OFF or ON	OFF: Taillight fuse not shut off ON: Taillight fuse shut off	-

Body Electrical > Power Distribution Box > Data List

Tester Display
Tail Light Fuse Shut Off Status

OK:

The Data List value displays "OFF".

OK

REPLACE LICENSE PLATE LIGHT ASSEMBLY RH

NG

10.	CHECK HARNESS AND CONNECTOR(POWER DISTRIBUTION BOX ASSEMBLY - REAR COMBINATION LIGHT ASSEMBLY AND LICENSE PLATE LIGHT ASSEMBLY

(a) Disconnect the S14 rear combination light assembly LH connector.

(b) Disconnect the S15 rear combination light assembly RH connector.

(c) Disconnect the U2 license plate light assembly LH connector.

(d) Disconnect the U3 license plate light assembly RH connector.

(e) Disconnect the U44 rear light assembly LH connector.

(f) Disconnect the U43 rear light assembly RH connector.

(g) Disconnect the cable from the negative (-) auxiliary battery terminal.

(h) Disconnect the 8F power distribution box assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
S14-2 (TL) - Body ground	Always	10 kΩ or higher
S15-2 (TL) - Body ground	Always	10 kΩ or higher
U2-1 (B) - Body ground	Always	10 kΩ or higher
U3-1 (B) - Body ground	Always	10 kΩ or higher
U44-1 (B) - Body ground	Always	10 kΩ or higher
U43-1 (B) - Body ground	Always	10 kΩ or higher
8F-30 - 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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