Q: How much should it cost to repair an airbag controller?

Hello - yes, by all means this should be repaired! Without it, your airbag is just dead weight in the vehicle, and offers no protection in the event of a crash. Was the vehicle in an accident which damaged the crash sensor? If so, having it evaluated by a reputable paint and body shop is a good idea for other, possibly safety-related damage. For the airbag controller and crash sensor repairs, check with a reputable paint and body shop, or your Nissan dealer for estimates and these repairs. Air bag controllers require specialized equipment and software to properly repair and reset. An improper repair here is actually dangerous to the driver, whether in a crash or not.