The group's survey of its 53 million members found few have heard of E15. While the Obama administration has approved E15 for cars made after 2001, only 12 million of the 240 million cars and light trucks on the road are approved by manufacturers for the fuel.
Drivers who use E15 could void their warranties, AAA warned in a release posted on its website Friday. The group urged the Environmental Protection Agency to withdraw its approval of the fuel, at least temporarily.
All cars now in use can handle E10, which contains 10 percent ethanol. E15 is currently available only at a handful of gas stations.
"It is clear that millions of Americans are unfamiliar with E15, which means there is a strong possibility that many motorists may improperly fill up using this gasoline and damage their vehicle," said Kevin Bakewell, AAA's chief public affairs officer. "Bringing E15 to the market without adequate safeguards does not responsibly meet the needs of consumers."