Check Led Headlight System

Trouble symptom: 

Headlight does not illuminate, or headlight is weak.

1. CHECK HEADLIGHT AND TAIL LIGHT ILLUMINATION. 
   1. Turn the ignition switch to ON.
   2. Set the lighting switch to the switch 1 (TAIL/PARKING) and switch 2 (HEAD).

   Do the headlight and tail light illuminate?

   Yes  The headlight system is normal.

   No  Go to  2.

2. CHECK BULB. 

   Display the data «LED HEADLAMP (RH) error Signal» and «LED HEADLAMP (LH) error Signal» using Subaru Select Monitor.

   NOTE: For detailed operation procedures, refer to "Application help".

   Is «Light On» displayed?

   Yes  Go to  3.

   No  Replace the headlight assembly. Refer to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .

3. CHECK CONNECTOR CONNECTION. 

   Check that the headlight connector is connected.

   Is the connector connected?

   Yes  Go to  4.

   No  Connect the connector.

   When it does not illuminate even though the switch is turned to ON: Go to  4.

4. CHECK HARNESS. 
   1. Disconnect the headlight connector.
   2. Turn the ignition switch to ON.
   3. Measure the voltage between the headlight connector and chassis ground.

   Connector & terminal 

   LH side 

   (F125) No. 1 (+) - Chassis ground (-):

   (F125) No. 3 (+) - Chassis ground (-):

   RH side 

   (F126) No. 1 (+) - Chassis ground (-):

   (F126) No. 3 (+) - Chassis ground (-):

   Is the voltage 10 - 13.5 V?

   Yes  Go to  5.

   No  Go to  6.

5. CHECK HEADLIGHT. 

   Apply battery voltage between headlight unit connector terminals.

   Terminals 

   Low beam 

   No. 3 (+) - No. 4 (-):

   High beam 

   No. 1 (+) - No. 2 (-):

   Does the headlight (low beam and high beam) come on at normal brightness?

   Yes  Go to  6.

   No  Replace the headlight assembly. Refer to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .

   If «LED HEADLAMP (RH) error Signal» and «LED HEADLAMP (LH) error Signal» indicate no illumination in step 2), check the malfunction signal line. If short circuit to power supply occurs, repair or replace the harness.

6. CHECK CURRENT DATA. 
   1. Turn the ignition switch to ON.
   2. Display the data of «Lighting I Lamp Output» and «Lighting II Lamp Output» using Subaru Select Monitor.

   Does the display switch between «OFF»←→«ON» when the lighting switch is moved from OFF position to the switch 1 (TAIL/PARKING) and switch 2 (HEAD) positions?

   Yes: 

   • Inspection: Refer to BODY CONTROL SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
   • Replacement: Refer to SECURITY AND LOCKS>BODY INTEGRATED UNIT .

   No  Go to  7.

7. 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  8.

   No  Replace the combination switch (light). Refer to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT) .

8. CHECK HARNESS. 
   1. Disconnect the connector of body integrated unit.
   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.

9. CHECK HARNESS. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the body integrated unit connector and the headlight and tail light connectors.
   3. Check the harness between body integrated unit and headlight and between body integrated unit and tail 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.