A blown engine may be holding up your Apple Watch delivery

A reported reliability problem with some Taptic Engine components may be constraining Apple Watch supply.

What kind of engine problem could be impacting your Apple Watch from arriving? The delivery truck breaking down is an obvious answer. But it could be Apple's own Taptic Engine holding things up.

Sources told the Wall Street Journal on Wednesday that Apple found some Taptic Engines produced for the watch to be unreliable. The internal part is what the Apple Watch uses for notification vibrations, so it's a critical component.

Some of the Taptic Engines were reportedly failing over time during internal reliability testing. As a result, Apple may have added a second supplier to assist AAC Technologies Holdings, which was the primary vendor for the small part. The Journal says that Nidec Corporation is now on tap to assist in producing additional Taptic Engines for the Apple Watch.

Adding a second parts supplier after primary product has begun isn't an overnight process though. Apple's production line could be slowed or stalled as it waits for additional, reliable components, which would further impact supply in the face of high demand.

I haven't seen a large number of complaints from those who have their Apple Watch indicating any defective devices have shipped. That's a good thing for Apple, although I suspect if there were a component problem in any watches that have been delivered, the company would likely swap them out for new watches.

Apple declined to comment on the particulars of the reported parts problem or its impact on Apple Watch delivery times.