DTC U0181: Lost Communication With Headlamp Leveling Control Module

DTC detecting condition: 

No data is received from auto headlight beam leveler control module.

Trouble symptom: 

Coordination control of auto headlight beam leveler control module does not operate normally.

1. CHECK CAN COMMUNICATION HARNESS. 

   Perform the basic diagnostic procedure to check for fault in CAN communication harness. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>BASIC DIAGNOSTIC PROCEDURE .

   Was the basic diagnostic procedure performed up to step 7?

   Yes:  Go to  2.

   No:  Perform the basic diagnostic procedure. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>BASIC DIAGNOSTIC PROCEDURE .

2. CHECK DTC (OTHER THAN U-CODE). 

   Check the displayed DTC.

   Is DTC other than U*** displayed? (Current malfunction)

   Yes:  Perform the diagnosis for DTCs other than the displayed U-code.

   No:  Go to  3.

3. CHECK DTC. 

   Check the displayed DTC.

   Is DTC U0181 displayed? (Current malfunction)

   Yes:  Go to  4.

   No:  Go to  6.

4. CHECK DTC. 
   1. Check CAN communication circuit. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>CAN COMMUNICATION CIRCUIT CHECK .
   2. Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .

      Is DTC U0181 displayed? (Current malfunction)

   Yes:  Go to  5.

   No:  Go to  6.

5. CHECK DTC. 

   Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .

   Is DTC U0181 detected in combination meter? (Current malfunction)

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

   No:  Replace the module that the DTC has been detected.

6. CHECK HARNESS. 
   1. Shake the harness and check for poor contact.
   2. Using the Subaru Select Monitor, read all DTCs. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .

   Is DTC U0181 displayed? (Current malfunction)

   Yes:  Repair the poor contact of harness or replace the harness.

   No:  Go to  7.

7. CHECK CONNECTOR. 

   Check the connector used for high speed CAN for poor contact.

   Is there poor contact of connector?

   Yes:  Repair the connector that has poor contact, or replace harness.

   No:  It is possible that temporary poor communication occurs. Delete the DTC.