DTC B2911: Steering Responsive Headlight Communication LH

DTC detecting condition:

LIN data no-receive or data abnormal of the SRH actuator is detected for 1 second or more.

Trouble symptom:

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

Failure detection pattern:

"Primary" (high-priority diagnosis)

Warning light/indicator light:

Auto headlight beam leveler warning light -
SRH warning light◦
ADB warning light◦
LED open circuit detection signal -

Wiring diagram:

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

Clearance light: Bulb model

Courtesy of SUBARU OF AMERICA, INC.
Clearance light: LED model

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Initialization is required after replacing the auto headlight beam leveler control module. Ref. to LIGHTING SYSTEM>AUTO HEADLIGHT BEAM LEVELER SYSTEM>OPERATION .
After replacing the headlight assembly, headlight beam adjustment is required. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY>ADJUSTMENT .

BASIC INSPECTION .
Before performing the diagnosis, perform basic inspection. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>GENERAL DESCRIPTION>INSPECTION .
NOTE:
- Check the battery and its installation condition.
- Check the related fuse.
- Visually check that the related connectors are properly connected. Also, check the related ground terminal for looseness and corrosion.
Is the check result OK?

Yes : GO TO 2.

No : Repair the defective part.
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 3.

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.

After the repair, GO TO 7.
CHECK HARNESS (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the headlight assembly LH.
3. Disconnect the connector from the headlight assembly RH.
4. Disconnect the connector from the auto headlight beam leveler control module.
5. 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. 15:
  
  (B78) No. 14 - (B122) No. 16:
  
  (B78) No. 13 - (B122) No. 11:
  
  (B78) No. 14 - (B122) No. 12:
Is the resistance less than 1 Ω?

Yes : GO TO 4.

No : Repair or replace the open circuit of harness.

After the repair, GO TO 7.
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 5.

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

After the repair, GO TO 7.
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 6.

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

After the repair, GO TO 7.
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 .

After replacement, GO TO 7.

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

After replacement, GO TO 7.
CHECK REPAIR .
1. Perform the inspection mode corresponding to DTC. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>INSPECTION MODE>PROCEDURE .
2. Confirm that DTC or cancel code is not stored and the malfunction is eliminated.
Is the check result OK?

Yes : Finish the diagnosis.

No : Perform the diagnosis according to the basic diagnostic procedure. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .