Auto Headlight System Check

WARNING: This page is about a different car, the 2015 Subaru Outback and 2015 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Check the headlight system before checking the auto headlight system. <Ref. to CHECK HEADLIGHT SYSTEM , INSPECTION, Headlight System.>

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK HEADLIGHT AND TAIL LIGHT ILLUMINATION . Turn the ignition to ON. Make the light control sensor vicinity dark. Set the lighting switch to AUTO position. Make the light control sensor vicinity bright. Turn the lighting switch to the OFF position and turn to the AUTO position again.	Do the headlight and tail light illuminate?	The auto headlight system is normal.	Go to step 2 .
2 CHECK CURRENT DATA . Using the Subaru Select Monitor, display the data of «Illumination Sensor Output». Measure the voltage when the area around the light control sensor, which was dark, becomes bright. NOTE: For detailed procedures, refer to "PC application help for Subaru Select Monitor". Illumination sensor output Dark condition: Approx. 0.6 V or less Bright condition: Approx. 3.0 V or more	Is the voltage output according to the brightness?	Go to step 5 .	Go to step 3 .
3 CHECK LIGHT CONTROL SENSOR . Check the light control sensor. <Ref. to INSPECTION , Light Control Sensor.>	Is the light control sensor normal?	Go to step 4 .	Replace the light control sensor.
4 CHECK HARNESS . Disconnect the connectors from body integrated unit and light control sensor. Check the harness between body integrated unit and light control sensor. Connector & terminal (i171) No. 8 - (i89) No. 1: (i171) No. 27 - (i89) No. 2: (i171) No. 28 - (i89) No. 3:	Is harness normal?	Check the body integrated unit and replace it if defective. <Ref. to BASIC DIAGNOSTIC PROCEDURE .>	Repair or replace the harness.
5 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 to the AUTO position?	Check the body integrated unit and replace it if defective. <Ref. to BASIC DIAGNOSTIC PROCEDURE .>	Go to step 6 .
6 CHECK COMBINATION SWITCH (LIGHT) . Turn the ignition to OFF. Check the combination switch (light). <Ref. to INSPECTION , Combination Switch (Light).>	Is the combination switch (light) normal?	Go to step 7 .	Replace the combination switch (light).
7 CHECK HARNESS . Disconnect the connectors of body integrated unit and combination switch (light). Check the harness between body integrated unit and combination switch (light).	Is harness normal?	Check the body integrated unit and replace it if defective. <Ref. to BASIC DIAGNOSTIC PROCEDURE .>	Repair or replace the harness.