Several of the investigations focus on previous recalls that appear to have failed to completely address known defects.
A few of the inquiries are related to previous recall campaigns that may not have effectively addressed a known defect.
In one case, VW launched a broad recall in 2015 for problematic steering wheel clocksprings in the 2010-2014 CC, Passat, Eos, Golf, Tiguan and Jetta. The NHTSA has since identified 852 reports of failures in vehicles that had received the recall remedy, prompting an engineering analysis that will determine if the automaker will be pressured to launch a follow-up campaign with a better fix.
The agency has also deepened its protracted investigation into claims of braking problems with the 2007-2009 Ford Fusion and Mercury Milan. Stuck ABS control valves are likely to blame for complaints of unexpectedly long pedal travel. Ford's internal analysis has identified the likely cause but the company does not see an unreasonable risk to safety.
"[Ford] acknowledged that stuck valves can result in increased pedal travel but maintains the affected brake circuit will develop pressure and respond if the brake pedal is pressed sufficiently," the NHTSA wrote in announcing the engineering analysis.
A seemingly related issue involves stuck valves in the ABS control system used in the 2009 Nissan Murano. The NHTSA has found nearly 500 complaints including 14 crash allegations and several injuries.
A separate investigation has been opened to explore claims of power steering loss in certain 2009-2012 BMW X5 vehicles that had been subject to a 2012 recall. The NHTSA has received 19 complaints of failures in repaired vehicles, with an "increasing trend" in the past 12 months.