The U.S. National Highway Traffic Safety Administration said it was opening a preliminary probe into vehicles manufactured by General Motors after receiving reports alleging engine failure.

The National Highway Traffic Safety Administration (NHTSA) has opened a preliminary probe into more than 877,000 trucks and SUVs built by General Motors. The agency’s Office of Defects Investigation (ODI) has received 39 complaints of engine failure due to a problem linked to faulty connecting rod bearings.

The National Highway Traffic Safety Administration on Friday opened an investigation into 870,000 cars manufactured by General Motors after receiving reports of engine failure.