Car Audio Head unit replacement issue


I recently bought a new 2013 Toyota Avalon & i want to replace the car head unit…but when i disconnected it, a yellow color warning sign appeared on the driver screen beside the speed meter saying that (Airbag sensor error)…the aftermarket installer got freaked out & asked me to consult 1st before changing the head unit to avoid any electrical problems that might be caused…i tried to consult the tech.guys in the Toyota dealer here in Dubai where i bought the car…they told me that they don’t know! of them said better not to tamper with it…the other told me that this light is just an indicator & no problems will happen other than that yellow light coming all the time…both sounded uncertain & that’s why i seek your guidance.