One problem related to air bag light on has been reported for the 2006 Audi A4. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Audi A4 based on all problems reported for the 2006 A4.
2006 Audi A4 cabriolet air bag light comes on and stays on. Dealer checked wiring connections under seat and light went out. 1week later it's back on. This time they sodered the wires and cleared the code. A week or 2 later it's back on and they did something else, what I'm not sure. 2 weeks after that light is on and they replace airbag in drivers seat. A few weeks after that it is on again and the dealer replaces the ring in the steering wheel ( clockspring??) 2 weeks after that the light is on again and the car is currently at the dealer. Am told it is a random fault. The car has about 35000 miles on it and the factory warranty is about to expire and the Audi certified warranty about to kick in. I purchased the car with about 33,000 miles on it.