Auto Headlight System Check

NOTE: Check the respective headlight systems before checking the auto headlight system.

Halogen headlight: Refer to LIGHTING SYSTEM>HEADLIGHT SYSTEM>INSPECTION>CHECK HALOGEN HEADLIGHT SYSTEM .
LED headlight: Refer to LIGHTING SYSTEM>HEADLIGHT SYSTEM>INSPECTION>CHECK LED HEADLIGHT SYSTEM .

CHECK HEADLIGHT AND TAIL LIGHT ILLUMINATION.
1. Turn the ignition switch to ON.
2. Make the light control sensor vicinity dark.
3. Set the lighting switch to AUTO position.
4. Make the light control sensor vicinity bright.
5. Turn the lighting switch to the OFF position and turn to the AUTO position again.
Do the parking light, headlight and tail light illuminate?

Yes The auto headlight system is normal.

No Go to 2.
CHECK CURRENT DATA.
1. Using the Subaru Select Monitor, display the data of «Illumination Sensor Output».
2. Measure the voltage when the area around the light control sensor, which was dark, becomes bright.
NOTE: For detailed operation procedures, refer to "Application help".

Illumination sensor output

Dark condition: Approx. 0.6 V or less

Bright condition: Approx. 3 V or more

Is the voltage output according to the brightness?

Yes Go to 5.

No Go to 3.
CHECK LIGHT CONTROL SENSOR.
Check the light control sensor. Refer to LIGHTING SYSTEM>LIGHT CONTROL SENSOR>INSPECTION .

Is the light control sensor normal?

Yes Go to 4.

No Replace the light control sensor.
CHECK HARNESS.
1. Disconnect the connectors from body integrated unit and light control sensor.
2. Check the harness between body integrated unit and light control sensor.
Connector & terminal

(B280) No. 19 - (i89) No. 2:

(B280) No. 29 - (i89) No. 1:

(B281) No. 1 - (i89) No. 3:

Is harness normal?

Yes Check the body integrated unit and replace it if defective.
- Inspection: Refer to BODY CONTROL SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
- Replacement: Refer to SECURITY AND LOCKS>BODY INTEGRATED UNIT .
No Repair or replace the harness.
CHECK CURRENT DATA.
Using the Subaru Select Monitor, display the data of «Lighting AUTO input».

Does the display switch between «OFF»←→«ON» when the lighting switch is moved from OFF position to the AUTO position?

Yes Check the body integrated unit and replace it if defective.
- Inspection: Refer to BODY CONTROL SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
- Replacement: Refer to SECURITY AND LOCKS>BODY INTEGRATED UNIT .
No Go to 6.
CHECK COMBINATION SWITCH (LIGHT).
1. Turn the ignition switch to OFF.
2. Check the combination switch (light). Refer to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT)>INSPECTION .
Is the combination switch (light) normal?

Yes Go to 7.

No Replace the combination switch (light). Refer to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT) .
CHECK HARNESS.
1. Disconnect the connectors of body integrated unit and combination switch (light).
2. Check the harness between body integrated unit and combination switch (light).
Is harness normal?

Yes Check the body integrated unit and replace it if defective.
- Inspection: Refer to BODY CONTROL SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
- Replacement: Refer to SECURITY AND LOCKS>BODY INTEGRATED UNIT .
No Repair or replace the harness.