Credit: Apple

Last week, Apple quietly updated one of its Apple Pencil support documents to warn users about the issue. The update was first spotted Monday by French site iGeneration. Specifically, Apple says a second-generation Apple Pencil that is charging inductively on an iPad Pro may interfere with signals from standard vehicle keyless entry devices.

The company notes that this “signal interference” could prevent users from unlocking their cars if the second-generation Apple Pencil-iPad Pro combo is nearby. The problem only impacts second-generation Apple Pencil models, and only those that are actively being charged wirelessly.

Apple recommends that users move their iPad Pro away from the key fob or simply remove their Apple Pencil and store it separately to fix the issue. It also notes that an Apple Pencil which is fully charged and is simply being stored magnetically won’t affect nearby key fobs.

That, and the fact that only currently charging styli cause the problem, suggests that the problem is tied to how the Qi wireless charging standard words.

Qi-based charging solutions use electromagnetic fields to transfer power from one device to another. Because of that, some Qi wireless charging solutions can cause issues with low-power radio signals — like those found on many keyless entry devices.

Apple, for its, part, didn’t specify which kinds of key fobs the Apple Pencil may affect. It only says that it could interfere with “keyless entry device(s).”

It’s likely that Apple is specifically referring to smart keys, which are newer key fobs designed to automatically unlock a car door when a user gets within a particular range of the vehicle.

These smart keys use short-range and lower-power radio signals, unlike the longer-range signals of most standard key fobs.

On the same note, Apple didn’t explicitly say that the Apple Pencil interferes with locking a car. It’s possible that the issue only surfaces with unlcoking a car with a smart key.

Presumably, any kind of Qi-based charging solution could cause this type of radio interference. If you’ve run into problems with push-to-start keyless solutions with a wireless charger in the car, the same type of problem may be to blame.