NHTSA Complaint #11533683 — 2023 SUBARU LEGACY

My wife is a petite woman, 4 feet 7 inches, 85pounds clothed. We bought the car March 29, 2023 and drove home, and the passenger airbag worked properly thru April 2. Behavior after that became erratic, passenger airbag sometimes on, sometimes not. Became more erratic and brought to dealer (Balise Subaru) April 12. Service technician reported system worked properly, no error codes. I asked Service manager to look at the car with my wife rather than a 180 pound technician sitting in it. He observed that with my wife in the passenger seat he would start and stop the car, and sometime the airbag was on, other times off even though she never moved or change position. He was going to check with Subaru, saying nothing in the system could be adjusted and it had a trigger weight of approximately 80.5 pounds. Erratic behavior became worse such that airbag was off 75% of the time. Tried various seat positions to no effect. Note: My wife sits 23 inches from the dashboard. On April 18 on a round trip to a doctor she weighed 84.6 pounds on a medical scale in normal indoor clothes, and wore a light coat (1.2 pounds) while in the car in both directions. The airbag was on the entire trip to the doctor, and off the entire trip home. Subaru responded she was so small and near trigger weight was the likely cause. Dealer did re zero the passenger seat, no change. Car has been at the dealer 3 times for this problem, and system has become somewhat less erratic such that the airbag is either on immediately or more often within 5 minutes of driving 50-60% of the time, yet my wife's weight has held steady. Two patterns I have found: Temperature sensitivity: more consistent when temp is in the 40s or 60s, worse in the 50s, and variable otherwise. Having the AC on seems to help so I'm wondering if the control unit or seat sensors are overheating, also high lateral forces on on-ramps will turn the airbag on. I also suspect the seat sensors lack precision and weigh my wife erratically.