Owners/service Manual problems of the 2008 Nissan Xterra

The vdc and slip light are constantly on when the battery has either died, or has been disconnected. Once the battery is disconnected the vdc is off and the slip system is off as well. After the battery was disconnected once again the vdc, slip system, and now my air bag light is now constantly flashing and illuminated. I've researched this problem and there are hundreds or thousands that have this same problem. In the owners manual it gives you a very vague description of how to reset this light. I've taken it to the manufacture to be reset, they say it's the vehicle's steering angle sensor that has to be reset, everytime you disconnect the battery, battery dies, alternator goes out, etc. It's $100+ everytime you have to have it reset. Surely this malfunction in their electrical system is not safe, especially if it means now my airbags won't deploy.