The August smart lock "Lock Jammed" error typically appears when the lock motor encounters physical resistance before reaching the fully locked position, or when the internal position sensor has drifted out of calibration. This creates a mismatch between where the lock thinks it is versus its actual position.
Quick answer
• Root cause: Physical friction from misaligned door hardware or drifted position sensor calibration • Primary fix: Align the door strike plate to eliminate friction, then recalibrate with door open • Applies to: August Wi-Fi Smart Lock (4th Gen) and August Smart Lock Pro (3rd Gen) • Success rate: High when physical alignment is addressed first
Symptoms
• App displays "Lock Jammed" even though the door is actually locked • "Calibration Failed" error appears during initial setup or recalibration • Lock motor makes whining or grinding sounds at the end of its rotation • Auto-Lock feature stops working because the lock can't determine its current state • Lock position shown in app doesn't match physical lock state
Quick checks
Physical resistance test: Unlock the door and manually turn the August lock by hand. Any sticky points or friction indicate door alignment issues that must be resolved before recalibration.
Wing latch inspection: Verify both side wing latches are fully clicked down onto the mounting plate. A loose wing latch causes the lock body to wobble during operation.
Tailpiece adapter verification: Confirm you're using the correct color adapter (Green/Blue/Yellow) as specified in the included chart. Wrong adapters create binding or excessive play.
Step-by-step fix
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Remove physical resistance first • Unlock the door completely • Loosen the mounting plate screws by 1-2 turns • Allow the August lock to center itself naturally on the deadbolt tailpiece • Manually turn the lock to verify smooth operation throughout the full range • Retighten mounting screws once movement is friction-free
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Address strike plate alignment if needed • If the deadbolt still binds when entering the strike plate, the hole may be too small due to seasonal door frame swelling • File the strike plate hole slightly larger, or replace with a tapered deadbolt that guides itself into the opening
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Perform door-open calibration • Open the August app and navigate to Lock Settings → Calibrate Lock • Keep the door open during the entire calibration process • Follow the app prompts to throw the bolt fully extended • Retract the bolt completely when prompted • Wait for "Calibration Successful" confirmation
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Test the completed calibration • Close the door and test multiple lock/unlock cycles • Verify the app status matches the physical lock position • Confirm Auto-Lock functionality if enabled
If it still isn't working
Check for motor damage: If you hear loud clicking or crunching sounds during operation, the internal gear train may be stripped from repeated jamming attempts. This requires lock replacement.
Inspect DoorSense if installed: The magnetic door position sensor can interfere with lock operation if mounted too close or if the magnet has shifted position.
Verify tailpiece engagement: Remove the August lock and inspect the deadbolt tailpiece for wear or damage. A worn tailpiece creates inconsistent engagement with the lock motor.
Reset and recalibrate again: Delete the lock from the app, perform a factory reset using the button sequence, and complete fresh setup with door open.
FAQ
Why must I calibrate with the door open? Door frame friction when closed can fool the position sensor into thinking it has reached full extension when it hasn't, creating false calibration reference points.
How often does calibration drift occur? Properly mounted locks maintain calibration for months or years. Frequent drift indicates loose mounting or door alignment issues that need physical correction.
Can I use WD-40 on the lock mechanism? No. Use only dry graphite lubricant on the deadbolt itself. Never apply liquid lubricants to the August lock motor or position sensors.
What's the difference between the tailpiece adapter colors? Each color accommodates different deadbolt tailpiece lengths and shapes. Using the wrong adapter creates either excessive play (loose) or binding (tight) that confuses the position sensor.