Quectel EM05 SIM card detection problem

IoT Modules LTE-A Module
1

Dear Quectel Support Team,

I am reaching out regarding an issue with my Quectel EM05 module. Recently, I have encountered a problem where the module fails to detect the SIM card, despite the card being correctly inserted.
Here are the details of the issue:
• The SIM card is present and functional, as it works in another device.
• There are 2 physical SIM slots, but only 1 is detected by Quectel
• The EM05 module is recognized by the system, but when checking the SIM status, it shows “absent” or “error” in the card status, even though the physical slot appears to be active.
• Here are the outputs returned when querying using qmicli:

• Here are the outputs returned when querying using Modemmanager:

I have tried various troubleshooting steps such as restarting the modem, switching between different firmware versions, and ensuring that all drivers are correctly installed. Unfortunately, the issue persists.
Could you please assist me in resolving this issue? Any guidance on potential firmware updates, configuration adjustments, or other steps to get the SIM detected would be greatly appreciated.

Thank you for your support. I look forward to your response.

2

Hi @alejandroInspectrail
I sent you the EM05 Hardware design reference manual by email. You can measure whether the corresponding pin voltage meets the requirements when connecting different SIM cards.

3

Hi Iyman,

the voltage seems to not be ok.. what should I do?

4

Dear Lyman-Q,

I have observed behaviour similar too

  • At times, AT+QSIMSTAT returns 0,1 (SIM present).
  • After some time, the same command returns 0,0 (SIM absent).
  • Performing a module reset using AT+CFUN=1,1 temporarily resolves the issue, but the behavior repeats: SIM Present → SIM Absent.

I noticed that you mentioned the possibility of insufficient voltage. Could you please advise on the recommended steps to measure and verify the SIM voltage? Additionally, if the voltage is indeed insufficient, I would appreciate your guidance on corrective actions to ensure stable SIM detection.

Thank you for your support and guidance.