One problem related to gas recirculation valve (egr valve) has been reported for the 2006 BMW 750. The most recently reported issues are listed below.
While driving about 20 miles per hour approaching a stop, the car shifted into netral and on the dash indicated the gear is now "n", then steering wheel locked and I could not turn to pull off the road. This was dangerous as I was in the middle of the road. After turning off the car, turning it back on, the problem disappears. If this fault happens on a highway, it can cause a fatal accident if the steering wheel locks and gear shifts to neutral. From reading BMW forums, they say possible causes could be the integrated supply module, transmission fault, electrical issue, or the smg sensor. Please read similar stories online. At the links below. . Read more...