The National Highway Traffic Safety Administration generally opens inquiries into car manufacturers after receiving numerous consumer complaints about an issue. Those investigations often lead to some type of safety recall. However, that wasn’t the case for two recently closed probes of more than 600,000 Ford and General Motors vehicles.

Reuters reports that regulators closed the investigations into 500,000 Ford vehicles and 100,000 GM vehicles without initiating a recall.

In closing both investigations, officials with NHTSA say that “closing of this investigation does not constitute a finding by NHTSA that a safety related defect does not exist.”

Back in July, NHTSA’s Office of Defects Investigations announced it would open a preliminary evaluation into the model year 2004 to 2007 Ford Crown Victoria, Mercury Grand Marquis and Mercury Marauder after receiving five complaints alleging interference between dislodged exhaust heat shields and the lower steering shaft.

One of the complaints alleged that the interference resulted in a crash on a highway entrance ramp. However, investigators say that the crash hold not be verified and was not supported by a police incident report.

Investigators say in their report [PDF] that information provided by Ford identified 10 additional incidents resulting in a low rate of 1.6 incidents per 100,000 vehicles sold.

Officials with NHTSA say that through the investigation they found there was a low probability of the incident occurring. Additionally, six of the reported complaints came from a single police department fleet and since the issue was fixed in 2011 no other complaints have been filed.

The investigation [PDF] in the GM vehicles – the 2014 Chevrolet Impala – was initiated in April after NHTSA received two reports of incidents of severe/sudden uncommanded braking resulting in rear impact collisions.

ODI analyzed all complaints related to allegations of unwanted brake activations while driving that were provided by GM or submitted to ODI from consumers and has not identified any additional incidents involving sudden, extended autonomous braking.

Through testing of the two rental vehicles involved in the complaints, GM determined that evidence indicates the accidents were caused when the drivers accidentally activated an electric park brake system.

U.S. regulators close probes into about 600,000 Ford, GM vehicles [Reuters]

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