Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2017 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE
Auto Headlight Beam Leveler System DTCS
AUTO HEADLIGHT BEAM LEVELER SYSTEM DIAGNOSTIC TROUBLE CODE IDENTIFICATION
| DTC | Item | Content of diagnosis | Reference |
|---|---|---|---|
| U0073 | CONTROL MODULE COMMUNICATION BUS OFF | Detected when CAN line abnormality is detected. | Ref. to DTC U0073 CONTROL MODULE COMMUNICATION BUS OFF , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| U0122 | LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE | Detected when CAN data from VDC (vehicle speed signal) does not arrive. | Ref. to DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| U0140 | LOST COMMUNICATION WITH BODY CONTROL MODULE | Detected when CAN data from body integrated unit (headlight ON signal) does not arrive. | Ref. to DTC U0140 LOST COMMUNICATION WITH BODY CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| U0416 | INVALID DATA RECEIVED FROM VEHICLE DYNAMICS CONTROL MODULE | Detected when data from VDC (vehicle speed signal) is abnormal. | Ref. to DTC U0416 INVALID DATA RECEIVED FROM VEHICLE DYNAMICS CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| U0422 | INVALID DATA RECEIVED FROM BODY CONTROL MODULE | Detected when CAN data from body integrated unit (headlight ON signal) is abnormal. | Ref. to DTC U0422 INVALID DATA RECEIVED FROM BODY CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| B2900 | AHL CONTROL | Detected when an error occurred in auto headlight beam leveler Control Module. | Ref. to DTC B2900 AHL CONTROL , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| B2902 | REAR HEIGHT SENSOR CIRCUIT | Detected when an error occurred in rear vehicle height sensor. | Ref. to DTC B2902 REAR HEIGHT SENSOR CIRCUIT , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| B2904 | LED HEADLIGHT CIRCUIT RH | Detected when malfunction is found in LED headlight (right side) trouble signal line. | Ref. to DTC B2904 LED HEADLIGHT CIRCUIT RH , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
| B2905 | LED HEAD LIGHT CIRCUIT LH | Detected when malfunction is found in LED headlight (left side) trouble signal line. | Ref. to DTC B2905 LED HEAD LIGHT CIRCUIT LH , Diagnostic Procedure with Diagnostic Trouble Code (DTC). |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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