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 AND DAYTIME RUNNING LIGHT SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to OFF.
   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. Disconnect the headlight assembly LH and RH connectors.
   2. Turn the ignition switch to OFF → ON.
   3. Turn the lighting switch to 2 (HEAD).
   4. Using a tester, measure the voltage between headlight assembly LH connector and chassis ground.

      Connector & 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)  .

   Using a tester, measure the resistance between headlight assembly LH connector and chassis ground.

   Connector & terminal 

   (B477) No. 4 - 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 and RH connectors.
   2. Turn the ignition switch to OFF → 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. Disconnect the auto headlight beam leveler control module connector.
   2. Using a tester, measure the resistance between auto headlight beam leveler control module connector and headlight assembly LH connector.

      Connector & terminal 

      (B150) No. 11 - (B477) No. 6:

   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 & terminal 

   (B150) 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.