Introduction
Is your Samsung Galaxy S21 5G, S21+ 5G, or S21 Ultra 5G showing “No SIM card detected” errors? A faulty SIM card reader could be the cause. This guide explains how a replacement can restore full functionality.
Why the SIM Card Reader Fails
The SIM reader connects the SIM tray to the motherboard. Damage can occur due to:
- Frequent SIM swaps
- Dust/moisture exposure
- Physical drops
Symptoms of a Bad SIM Reader
✔ “No SIM” or “Invalid SIM” errors
✔ Intermittent signal loss
✔ 5G/4G network failures
How to Replace the SIM Card Reader
- Power Off – Shut down your phone.
- Remove the SIM Tray – Use an ejector tool.
- Open the Back Panel – Heat gun + pry tool required.
- Disconnect the Battery – Safety first!
- Replace the Reader – Unplug the old one and install the new SIM card reader for Samsung S21 5G series.
- Reassemble & Test – Check SIM detection before sealing.
Why Use an OEM-Compatible Reader?
Cheap replacements may fail quickly. A high-quality SIM card reader for Samsung Galaxy S21 5G series ensures:
- Reliable SIM detection
- Stable 5G connectivity
- Long-lasting performance
Final Thoughts
Replacing the SIM card reader is a quick fix for persistent “No SIM” errors. Whether you DIY or visit a repair shop, ensure you use a compatible, high-quality part.
