How to fix face id

What exactly do you mean when you say, "not working"? Are you getting an error message? Does it fail when trying to register your face? Or does it just not unlock the phone when you try to use it?

There are several parts to the Face ID system, and we can't even guess what might be wrong without more information. Tell us exactly what it's doing or not doing and we'll see what we can do to help.

However, you should be aware that if any component of your Face ID system has failed, only Apple can repair it. The individual parts are paired to the motherboard, and only Apple can do that pairing, so even if you replace a defective part, it still won't work. It's my understanding that the Repair Assistant available on iOS 18 and later can pair Face ID components using genuine Apple parts, but only on iPhone 12 and later models, so it won't help with an iPhone X, XS, XR or 11.