One problem related to air bag not deploy has been reported for the 2008 BMW 335. The most recently reported issues are listed below.
Passenger safety restraint system malfunctions, when a passenger is sitting in the passenger seat, the system malfunctions. This means the airbag will not deploy should there be a crash. This very issue is a cause of a recall by BMW for 2007 models, but early 2008 models are not currently covered despite this being a very common issue with this model.