One problem related to air bag not deploy has been reported for the 2002 BMW X5. The most recently reported issues are listed below.
We were backing up the car from the restaurant and driver side air bag and curtain air bag popped open but not deployed with air for no reason. Took the car to dealer they said sensor underneath the car initiated, and to repair costs will be $4,000. 00. I don't have money to fix the car and they released the car to me. The bags are not deployed and afraid of deploying while driving.