Nissan security light on 4

https://immobilizerfaultnissanreview.dovetailscope.com/posts/what-does-the-car-with-key-symbol-mean-understanding-immobilizer-fault-nissan

That little red car icon with a key on your Nissan dashboard is the security light. When it's blinking fast after you lock the doors, it means the alarm system is active and watching. A slow blink usually means there's an issue, like a door sensor not closing properly or a problem with the key fob signal. It's a normal sign of a working system, but a steady light after startup might indicate a fault needing a dealer check.