Toyota Yaris: Lighting System / Headlight Dimmer Switch Circuit

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Exterior / Lighting (ext) / Lighting System / Headlight Dimmer Switch Circuit

DESCRIPTION

The steering sensor receives the following switch information:

  • Light control switch in tail, head or AUTO position
  • Dimmer switch in high, low or high flash (pass) position
  • Fog light switch in front or off position

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

Click here

PROCEDURE

1.

READ VALUE USING GTS

(a) Read the Data List according to the display on the GTS.

Chassis > Steering Angle Sensor > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Light OFF Switch

Light control switch off position signal

OFF or ON

OFF: Light control switch not in off position

ON: Light control switch in off position

-

Auto Light Switch

Light control switch AUTO position signal

OFF or ON

OFF: Light control switch not in AUTO position

ON: Light control switch in AUTO position

-

Head Light Switch (Tail)

Light control switch tail position signal

OFF or ON

OFF: Light control switch in neither tail nor head position

ON: Light control switch in tail or head position

-

Head Light Switch (Head)

Light control switch head position signal

OFF or ON

OFF: Light control switch not in head position

ON: Light control switch in head position

-

High Beam Main Switch

Dimmer switch high position signal

OFF or ON

OFF: Dimmer switch not in high position

ON: Dimmer switch in high position

-

Passing Light Switch

Dimmer switch high flash position (pass) signal

OFF or ON

OFF: Dimmer switch not in high flash position

ON: Dimmer switch in high flash position

-

Front Fog Light Switch

Front fog light switch signal

OFF or ON

OFF: Front fog light switch off

ON: Front fog light switch on

-

Rear Fog Light/Bad Weather Switch

Rear fog light switch signal

OFF or ON

OFF: Rear fog light switch off

ON: Rear fog light switch on

-

Chassis > Steering Angle Sensor > Data List

Tester Display

Light OFF Switch

Auto Light Switch

Head Light Switch (Tail)

Head Light Switch (Head)

High Beam Main Switch

Passing Light Switch

Front Fog Light Switch

Rear Fog Light/Bad Weather Switch

OK:

Normal conditions listed above are displayed.

NG

GO TO STEP 8

OK

2.

READ VALUE USING GTS

(a) Read the Data List according to the display on the GTS.

Body Electrical > Main Body > Data List

Tester Display

Measurement Item

Range

Diagnostic Note

Light Control Switch (HEAD)

Light control switch head position signal

OFF: Light control switch not in head position

ON: Light control switch in head position

-

Chassis > Steering Angle Sensor > Data List

Tester Display

Measurement Item

Range

Diagnostic Note

Head Light Switch (Head)

Light control switch head position signal

OFF: Light control switch not in head position

ON: Light control switch in head position

-

Body Electrical > Main Body > Data List

Tester Display

Light Control Switch (HEAD)

Chassis > Steering Angle Sensor > Data List

Tester Display

Head Light Switch (Head)

OK:

Normal conditions listed above are displayed.

Result

Proceed to

OK

A

NG ("Steering Angle Sensor" side abnormality)

B

NG ("Main Body" side abnormality)

C

NG ("Steering Angle Sensor" and "Main Body" are abnormality)

D

A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

B

REPLACE STEERING SENSOR

D

GO TO STEP 4

C

3.

CHECK HARNESS AND CONNECTOR (STEERING SENSOR - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU])

(a) Disconnect the H4 main body ECU (multiplex network body ECU) connector.

(b) Disconnect the H39 steering sensor connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

H4-26 (HEAD) - H39-7 (HEAD)

Always

Below 1 Ω

H4-26 (HEAD) or H39-7 (HEAD) - Body ground

Always

10 kΩ or higher

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

INSPECT TURN SIGNAL SWITCH

Click here

NG

REPLACE TURN SIGNAL SWITCH

OK

5.

INSPECT STEERING WHEEL SWITCH HOUSING

Click here

NG

REPLACE STEERING WHEEL SWITCH HOUSING

OK

6.

CHECK HARNESS AND CONNECTOR (STEERING SENSOR - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU])

(a) Disconnect the H4 main body ECU (multiplex network body ECU) connector.

(b) Disconnect the H39 steering sensor connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

H4-26 (HEAD) - H39-7 (HEAD)

Always

Below 1 Ω

H4-26 (HEAD) or H39-7 (HEAD) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

READ VALUE USING GTS

(a) Read the Data List according to the display on the GTS.

Body Electrical > Main Body > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Light Control Switch (HEAD)

Light control switch head position signal

OFF or ON

OFF: Light control switch not in head position

ON: Light control switch in head position

-

Body Electrical > Main Body > Data List

Tester Display

Light Control Switch (HEAD)

OK:

Normal conditions listed above are displayed.

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE STEERING SENSOR

8.

INSPECT TURN SIGNAL SWITCH

Click here

NG

REPLACE TURN SIGNAL SWITCH

OK

9.

INSPECT STEERING WHEEL SWITCH HOUSING

Click here

OK

REPLACE STEERING SENSOR

NG

REPLACE STEERING WHEEL SWITCH HOUSING

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