G-Sensor Not Locking Files: What to Check

What locking means

The g-sensor on a dash cam detects sudden acceleration or deceleration and protects the current video clip from being overwritten by loop recording. Depending on the model, it may lock the clip at the moment of impact, the clip just before impact, or both. Locked files are typically stored in a separate event, lock, or emergency folder.

If you never see locked files after a real bump, the feature is either not active, not sensitive enough, or the impact is not reaching the sensor. Motor vehicle crashes are a leading cause of death in the United States, the CDC reports, so a protected clip can matter when you need evidence later. If you are new to the feature, read what a dash cam g-sensor does before changing settings.

Check the g-sensor sensitivity setting

Open the camera menu, usually on the screen or in the companion app, and look for G-sensor, Impact detection, Collision detection, or Event sensitivity. If the setting is Off, turn it on. If it is Low, raise it to Medium or High. Save the setting and drive over a small bump to confirm the camera locks a clip.

Keep in mind that the sensitivity scale differs by model. Some cameras use Low, Medium, and High, while others use numbers. A high setting may lock files when you hit potholes; a low setting may ignore a serious collision. Start with a middle value and adjust based on how often false triggers appear. If rough roads create too many locked clips, see the g-sensor false triggers guide.

• Off, Low, Medium, High, or a numeric scale
• Impact detection
• Collision detection
• Event sensitivity

Check the mount and power

A loose mount can absorb the shock or let the camera rotate, so the sensor may not register a hard stop. Tighten the suction cup or adhesive mount, reattach the camera, and make sure the lens does not wobble. Clean both surfaces before pressing a suction cup back into place.

The power connection also matters. A momentary power loss can reboot the camera before it locks a clip. Inspect the cable, the accessory socket, and the fuse tap or hardwire kit. If the camera restarts when you hit a bump, it may miss the lock window. Review the hardwire kit guide if you need help tracing the power path.

Check the card and event folders

Locked clips may be hidden in a separate folder such as Event, Lock, Emergency, or File Protect. If you look only at the normal DCIM folder, you may think nothing was locked. Open the camera app or view the card on a computer and sort by folder.

Memory card problems can also break locking. A nearly full card, a card with corrupt files, or a card that is too slow can prevent the camera from writing the protected clip. Back up any footage you want to keep, then format the card in the camera. If you see repeated errors, consider a high endurance microSD card.

Test with a firm tap

To confirm the lock function works, park safely and give the camera a firm tap with your hand. It does not take a crash-level impact. If the g-sensor is set to Medium or High, a tap or a quick stop should create a locked clip. Then check the event folder.

Do not hammer the windshield. A firm tap to the camera body is enough. If the camera records the clip but does not lock it, move on to the card and folder checks. If it still does not lock, the sensor may be faulty or the firmware may need an update. Check the firmware update guide before deciding the camera cannot be fixed.

Firmware and model quirks

Sometimes the g-sensor is working, but the camera only locks files when the impact exceeds a minimum threshold that you cannot change. Some models require you to enable event recording in the setup menu for lock files to appear. If you updated the firmware recently, the menu wording or default sensitivity may have changed. If the camera has a companion app, open the g-sensor settings in the app and confirm they match the on-screen menu.

No dash cam can lock a file if the camera shuts down before the sensor detects motion. A crash that severs power can end recording before the lock is written. Parking mode and event recording settings can interact with the g-sensor, so check those pages if you rely on parked coverage.

Use manual save as a backup

Most dash cams have a manual save button or a menu command. Pressing it protects the current clip from overwriting, independent of the g-sensor. On many models, the button is marked with a lock icon. If you are ever in a collision and the g-sensor does not react, press that button.

Manual save is especially useful in parking mode or when the impact is slow, such as a vehicle rolling into yours. The g-sensor may not feel a gentle push, but the clip still matters for insurance. If your camera makes manual saving difficult, consider a model with a dedicated manual save button.

What to pick for your use

Questions

Why are my locked files missing?

Locked files may be stored in a separate Event, Lock, Emergency, or File Protect folder, so check those folders before assuming the g-sensor did not work. A memory card error can also prevent the camera from writing the protected clip, so back up your footage and format the card in the camera.

What g-sensor sensitivity should I use?

Start with the middle setting or one step above the middle. If the camera locks files too easily, lower the sensitivity. If it ignores real impacts, raise it. The best setting depends on your vehicle, your roads, and how firmly the camera is mounted.

Can a faulty memory card stop the g-sensor from locking files?

Yes. A card that is nearly full, corrupted, or too slow can prevent the camera from writing the locked clip. Format the card in the camera and use a high endurance microSD card if the problem repeats.

What should I do if a crash does not lock the file?

Press the manual save button as soon as it is safe to do so. Then check the g-sensor sensitivity, tighten the mount, inspect the power connection, and review the event folders. If the camera still does not lock files during a firm tap test, update the firmware or consider replacing the camera.

How do I know if the g-sensor is working at all?

Use the firm tap test. Park safely, tap the camera body with your hand, and then check the event folder. If a clip appears in the protected folder, the g-sensor is working and the problem is likely sensitivity, mount, power, or card related.