U.S. safety regulators opened a preliminary investigation into the Chrysler Group's 2007 Jeep Wrangler after receiving complaints of engine stall at highway speed.

The National Highway Traffic Safety Administration said that it has received 53 complaints and that a majority of those drivers said they experienced stalling on more than one occasion. In 12 cases, drivers complained of losing electrical power and lighting at the same time as the vehicles stalled.

No accidents or fatalities were reported, a report summary on the agency's Web site said.