Toyota Corolla Cross: Taillight Relay Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the taillight and license plate light.

WIRING DIAGRAM

for LED Type Parking Light

for Bulb Type Parking Light

CAUTION / NOTICE / HINT

NOTICE:

• First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CAN communication malfunctions before troubleshooting this symptom.

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• 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.	CHECK VEHICLE TYPE

(a) Check vehicle type.

Result	Proceed to
for LED Type Parking light	A
for Bulb Type Parking light	B

B

GO TO STEP 12

A

5.	INSPECT REAR COMBINATION LIGHT ASSEMBLY LH

(a) Disconnect the S14 rear combination 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

6.	INSPECT REAR COMBINATION LIGHT ASSEMBLY RH

(a) Disconnect the S15 rear combination 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

7.	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

8.	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

9.	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

10.	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

11.	CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - TAIL RELAY CIRCUIT)

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

(b) Disconnect the S15 rear combination 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

12.	INSPECT HEADLIGHT ASSEMBLY LH (PARKING LIGHT)

(a) Disconnect the A162 headlight assembly LH (parking light) 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 HEADLIGHT ASSEMBLY LH

NG

13.	INSPECT HEADLIGHT ASSEMBLY LH (FRONT SIDE MARKER LIGHT)

(a) Disconnect the A165 headlight assembly LH (front side marker light) 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 HEADLIGHT ASSEMBLY LH

NG

14.	INSPECT HEADLIGHT ASSEMBLY RH (PARKING LIGHT)

(a) Disconnect the A161 headlight assembly RH (parking light) 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 HEADLIGHT ASSEMBLY RH

NG

15.	INSPECT HEADLIGHT ASSEMBLY RH (FRONT SIDE MARKER LIGHT)

(a) Disconnect the A164 headlight assembly RH (front side marker light) 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 HEADLIGHT ASSEMBLY RH

NG

16.	INSPECT REAR COMBINATION LIGHT ASSEMBLY LH

(a) Disconnect the S3 rear combination 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

17.	INSPECT REAR COMBINATION LIGHT ASSEMBLY RH

(a) Disconnect the S6 rear combination 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

18.	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

19.	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

20.	CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - TAIL RELAY CIRCUIT)

(a) Disconnect the A162 headlight assembly LH (parking light) connector.

(b) Disconnect the A165 headlight assembly LH (front side marker light) connector.

(c) Disconnect the A161 headlight assembly RH (parking light) connector.

(d) Disconnect the A164 headlight assembly RH (front side marker light) connector.

(e) Disconnect the S3 rear combination assembly LH connector.

(f) Disconnect the S6 rear combination assembly RH connector.

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

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

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

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

(k) Disconnect the 8E power distribution box assembly connector

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A162-2(B) - Body ground	Always	10 kΩ or higher
A165-2(B) - Body ground	Always	10 kΩ or higher
A161-2(B) - Body ground	Always	10 kΩ or higher
A164-2(B) - Body ground	Always	10 kΩ or higher
S3-2 (TL) - Body ground	Always	10 kΩ or higher
S6-2 (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
8E-18 - 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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