General Motors is recalling nearly 780,000 crossover SUVs because the rear power lift gates can suddenly fall and hit people.
The company said Friday that it has 56 reports of injuries caused by the problem.
The recall covers the Buick Enclave from the 2008 to 2012 model years and the Chevrolet Traverse from 2009 to 2012. Also affected are the GMC Acadia from 2007 to 2012 and Saturn Outlook from 2007 to 2010.
GM said in documents posted Friday by the U.S. National Highway Traffic Safety Administration that dirt can get into the gas struts that hold up the power rear hatches, causing them to wear and fail. A rod system designed to close the hatches slowly if the struts fail may not work because the software controlling it may not detect the problem, GM said in a statement.
Dealers will replace faulty struts and update lift gate control motor software to prevent rapid closing. The company has not yet come up with a schedule for when the recall will begin.
The problem surfaced in September 2010 when a company driver reported a lift gate failure. GM investigated, but because the rate of incidents was low at the time, decided to continue monitoring the problem. In November of last year, GM got two more reports of problems and opened another investigation. This time, it decided a recall was needed, according to documents GM filed with NHTSA.
The 56 injury reports were discovered during the second investigation by checking complaints to the company and the government, spokesman Alan Adler said.
GM says struts on SUVs built after March 1, 2012 were installed differently and are less vulnerable to dirt particles.