DTC B2911: Steering Responsive Headlight Communication LH

DTC detecting condition: 

No  : signal reception from left SRH actuator is detected for five seconds continuously.

Trouble symptom: 

The steering responsive headlight does not operate. SRH indicator blinks.

Wiring diagram: 

Headlight beam leveler system Ref. to WIRING SYSTEM>HEADLIGHT BEAM LEVELER 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 (DIAGNOSTICS)>CLEAR MEMORY .
   3. Read the DTC of [Headlight/Foglight] using the Subaru Select Monitor. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2911 displayed? (Current code)

   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 HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the headlight assembly LH and RH connectors.
   3. Disconnect the auto headlight beam leveler Control Module connector.
   4. Using a tester, measure the resistance between auto headlight beam leveler Control Module connector and headlight assembly LH connector.

      Connector & terminal 

      (B78) No. 13 - (B122) No. 12:

      (B78) No. 14 - (B122) No. 16:

   Is the resistance less than 1 Ω?

   Yes  : Go to  3.

   No  : Repair or replace the open circuit of harness.

3. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

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

   Connector & terminal 

   (B78) No. 13 - Chassis ground:

   (B78) No. 14 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  4.

   No  : Repair or replace the short circuit of the harness.

4. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY)  .
   1. Turn the ignition switch to ON.
   2. Using a tester, measure the voltage between auto headlight beam leveler Control Module connector and chassis ground.

      Connector & terminal 

      (B78) No. 13 (+) - Chassis ground (-):

      (B78) No. 14 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes  : Go to  5.

   No  : Repair or replace the short circuit of the harness.

5. CHECK DTC  .
   1. Turn the ignition switch to OFF.
   2. Connect all the disconnected connectors.
   3. Turn the ignition switch to ON.
   4. Read the DTC of [Headlight/Foglight] using the Subaru Select Monitor. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2910 displayed in addition to B2911? (Current code)

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

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