How to fix "unknown part" showing on my iPhone?

The unknown part error is as important as the Check Engine light in your car.

—It needs to be serviced A.S.A.P.—

Service Checklist:

• iPhone service pricing.
• Check AppleCare Coverage.
• Get your iPhone ready for service.

Click ▶︎ Start a Service Request. ⚛️

Need more help?

• Chat now or call 1-800-APLCARE.
• International Support.

Click ▶︎ Check Repair Status. 🔧

If you had it serviced by an unauthorized service provider, the only way to get rid of that is to buy a new phone.

Otherwise, make an appointment at the Genius Bar of your local Apple Store.