DTC B2905: Led Head Light Circuit LH

DTC detecting condition: 

LED headlight (LH) malfunction signal line error is detected for 2 seconds or more.

Trouble symptom: 

LED headlight malfunction, LED headlight indicator illuminates.

Wiring diagram: 

• Headlight beam leveler system Ref. to WIRING SYSTEM>HEADLIGHT BEAM LEVELER SYSTEM>WIRING DIAGRAM .
• Headlight system Ref. to WIRING SYSTEM>HEADLIGHT SYSTEM>WIRING DIAGRAM .

  Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch OFF → ON.
   2. Using the Subaru Select Monitor, perform the clear memory of [Headlight/Foglight]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Turn the ignition switch to OFF - ON.
   4. Turn the lighting switch to 2 (HEAD).
   5. Read the DTC of [Headlight/Foglight] using the Subaru Select Monitor. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2905 displayed? (Current malfunction)

   Yes:  Go to  2 .

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time.

   Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK DATA MONITOR  .

   Using the Subaru Select Monitor, check the following items in the [Data monitor] of [Headlight/Foglight]. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DATA MONITOR .

   • LED HEADLAMP(LH) error Signal

   Does the data display [Extinction]?

   Yes:  Replace the auto headlight beam leveler control module. Ref. to LIGHTING SYSTEM>AUTO HEADLIGHT BEAM LEVELER CONTROL MODULE .

   No Go to 3  .

3. CHECK THE HEADLIGHT SYSTEM POWER SUPPLY CIRCUIT  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the headlight assembly LH and RH connectors.
   3. Turn the ignition switch to ON.
   4. Turn the lighting switch to 2 (HEAD).
   5. Using a tester, measure the voltage between headlight assembly LH connector and chassis ground.

      Connector and terminal 

      (B477) No. 1 (+) - Chassis ground (-):

   Is the voltage 10 - 13 V?

   Yes:  Go to  4 .

   No:  Repair the headlight system.

4. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Using a tester, measure the resistance between headlight assembly LH connector and chassis ground.

      Connector and terminal 

      (B477) No. 3 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  5 .

   No:  Repair or replace the open circuit of harness.

5. CHECK HEADLIGHT SYSTEM  .
   1. Connect the headlight assembly LH connector.
   2. Turn the ignition switch to ON.
   3. Turn the lighting switch to 2 (HEAD).

   Does the headlight come on at normal brightness?

   Yes:  Go to  6 .

   No:  Replace the headlight. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .

6. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the auto headlight beam leveler control module connector.
   3. Using a tester, measure the resistance between auto headlight beam leveler control module connector and headlight assembly LH connector.

      Connector and terminal 

      (B616) No. 11 - (B477) No. 5:

   Is the resistance less than 10 Ω?

   Yes:  Go to  7 .

   No:  Repair or replace the open circuit of harness.

7. CHECK HARNESS (OPEN CIRCUIT)  .

   Using a tester, measure the resistance between the auto headlight beam leveler control module connector and chassis ground.

   Connector and terminal 

   (B616) No. 2 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Replace the auto headlight beam leveler control module. Ref. to LIGHTING SYSTEM>AUTO HEADLIGHT BEAM LEVELER CONTROL MODULE .

   No:  Repair or replace the open circuit of harness.