DTC B2900: AHL Control

DTC detecting condition: 

The microcomputer malfunction in the auto headlight beam leveler control module is detected.

Trouble symptom: 

The auto headlight beam leveler does not operate.

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

1. 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.

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

   Is any of DTC B2900, B2916, B2917, B2918, B2919 or B291A displayed? (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  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  3.

3. 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 .