A problem has emerged with the Segway Human Transporter, the $5,000 high-technology scooter that has computerized gyroscopes to keep it from falling over.

It falls over, at least under some conditions.

The Consumer Product Safety Commission and Segway LLC announced a recall on Friday of all 6,000 Segways, which, the announcement said, tend to tip forward when the batteries are low and the rider does something that requires a quick burst of power, like speeding up abruptly or trying to bump over an obstacle.

A user who has such an accident must first ignore a number of signals from the Segway to get to the hazardous tipping point. The machines have a prominent battery level indicator built into the handlebars, and as power drains below a certain level, a light comes on, an alarm sounds, and the handlebars vibrate. A Segway can be charged at any power outlet with a cord that is identical to those used in most personal computers.

The company, based in Manchester, N.H., has so far received three reports of riders falling; one of those users needed stitches for a head injury.

The recalled machines, the company said, will get a software upgrade that will cause them to give their battery warnings earlier and to shut down before low power levels become a problem.

The Segway was introduced last November with great fanfare and with coverage by a largely enthusiastic press corps.

Even before its debut, the Segway drew much attention, because it was cloaked in secrecy. Since its introduction, the company has hired an army of lobbyists in an effort to get state and local governments to change laws that bar motorized vehicles from sidewalks.