One problem related to front air bag sensor control has been reported for the 1998 Cadillac STS. The most recently reported issues are listed below.
The main air bag from the steering wheel was set off with the car running and in park. The car was not moving nor was there any collision to set off the air bag. Later investigation by Cadillac/gm determined faulty sensors that caused the air bag to deploy improperly which created/creates a potentially dangerous situation.