The B1312 code on your 2020 Audi A4 indicates a fault in the front right (passenger) door lock actuator circuit. This code affects your A4's convenience/comfort system, specifically indicating the passenger door lock is malfunctioning.
Understanding B1312 on Audi A4
The passenger door has its own door control module that operates the lock actuator, window motor, and mirror functions. Code B1312 indicates the comfort control system has detected a fault specifically with the front right door lock circuit.
Common Symptoms
- Passenger door won't lock remotely
- Passenger door won't unlock remotely
- Door lock makes clicking but doesn't lock
- Incomplete lock cycles
- Central locking works on other doors
Primary Causes
- Door lock actuator motor failure
- Door control module J387 fault
- Wiring damage in passenger door jamb
- Connector corrosion in door
- Mechanical latch binding or damage
- Comfort control module communication issue
Diagnostic Procedure for 2020 Audi A4
Using VCDS, access door control module J387 (front passenger door). Check for specific faults and actuator feedback. Command lock/unlock from scan tool and observe response. Inspect door jamb wiring for breaks. Check door latch for mechanical binding. Verify connector condition inside door.
Repair Solutions
Replace faulty door lock actuator/latch assembly. Repair broken wiring in door jamb. Replace door control module J387 if it's not commanding properly. Clean corroded connectors. Free up binding latch mechanism with lubrication if mechanical issue. Clear codes and verify multiple lock/unlock cycles.