The National Highway Traffic Safety Administration has opened a preliminary investigation into whether an estimated 30,000 2012 model-year Volkswagen Passat and CC sedans have a defective steering column control module that might cause the driver air bag to fail.

The federal agency’s office of defects investigation has received nine reports alleging failure of the steering column control module (SCCM) in 2012 Volkswagen Passat and CC vehicles. Located within the steering column, the module uses a spiral conductor to electrically connect the steering wheel to the car’s electrical system. Typical steering wheel-mounted electrical components include the air bag, the horn and electronic controls for such equipment as the radio.

Investigators will determine whether the presence of any defect in the SCCM could affect performance of the driver air bag in the event of a crash. Volkswagen is cooperating with the probe.

Consumers have reported that SCCM failures in the vehicles are sometimes accompanied by an audible noise from the steering column and illumination of the air bag warning light on the dash.