How to Fix Apple iPhone SIM Card Not Detected

Quick Diagnosis

A 'No SIM Card Installed' error on an iPhone is typically caused by a misaligned SIM card tray, dirt on the gold contact pads, or a loss of contact pressure inside the physical reader slot.

Technical diagnostic blueprint diagram for the Apple iPhone showing symptoms of SIM Card Not Detected.

Step-by-Step Resolution

  1. 1

    Locate the physical SIM card tray on the side of the iPhone frame.

  2. 2

    Insert a paperclip or a dedicated SIM ejector tool into the pinhole next to the tray.

  3. 3

    Press firmly straight in until the tray pops out; do not angle the tool to avoid mechanical bending.

  4. 4

    Remove the SIM card from the tray and inspect it for physical scratches or cracks.

  5. 5

    Wipe the gold-plated contact pad surface of the SIM card clean using a lint-free cloth.

  6. 6

    Use a can of compressed air or a dry bulb blower to blow out any dust or lint inside the SIM reader slot cavity.

  7. 7

    Place the SIM card back into the tray, ensuring it sits flat and aligned with the notch.

  8. 8

    Insert the tray back into the iPhone in the correct orientation and press it flush with the frame.

Alternative Causes & Edge Cases

  • On iPhone 12 and 13 models, the SIM reader is a modular hardware part inside the chassis; a hard drop can dislodge its motherboard socket, leading to intermittent 'No SIM' warnings.
  • On dual-SIM models, physical deformation of the double-sided SIM tray clip will prevent the bottom card from aligning with the spring contacts.