General Motors Co. is recalling 779,000 SUVs because the power liftgate may fall unexpectedly, reports The Detroit News. The problem is linked to 56 injuries.

The recall covers the 2009-12 Chevrolet Traverse, 2008-12 Buick Enclave, 2007-12 GMC Acadia and 2007-10 Saturn Outlook.

GM said Friday the gas struts that hold up the liftgate may prematurely wear. According to the automaker, “These vehicles have a prop rod recovery system intended to return the liftgate to the closed position in a slow and controlled manner if the liftgate’s gas struts are no longer capable of supporting the weight of the liftgate. However, in these vehicles, the prop rod recovery system software may be unable to detect or stop a liftgate with prematurely worn gas struts from falling too quickly after the liftgate is opened.”

The Detroit automaker opened and closed an investigation in 2010 into the issue after didn’t find a trend. After reports of problems with struts at Toyota Motor Corp. and Honda Motor Co., the National Highway Traffic Safety Administration conducted a review that included GM.

In November 2014, GM’s Emerging Issues group investigated two Speak Up For Safety cases related to power liftgates, and a formal GM investigation was opened March 17.

GM dealers will reflash the power liftgate actuator motor with a new software calibration. Dealers applying the reflash to a vehicle will verify that the power liftgate is working.

Separately, GM’s recall of nearly 200,000 Hummer SUVs for fire risks announced this week was prompted by NHTSA after GM had earlier decided not to recall the vehicles, documents posted Friday show.

GM had reviewed complaints and opened an investigation in December “and concluded that the blower motor connector issue was isolated to the subject Hummer H3 and H3T vehicles.” In April, GM’s Safety Field Action Decision Authority decided to close this investigation without a recall.

GM is required to review those decisions with NHTSA under a consent order that will last until at least May 2016.

“When GM subsequently reviewed this decision with NHTSA, NHTSA asked additional questions and directed GM to additional (complaints) that appeared to be related to this issue,” GM said in its recall filing. After further discussion with NHTSA, GM decided to conduct a recall.