BG95-M3 not responding after AT+QIACT=1

I am using BG95-M3 connected with the UART port. Around 80% of times the modem initialises correctly and I am able to send and receive data using HTTP POST etc. However, in the 20% where it fails I am getting no response to the AT+QIACT=1 command. I am waiting well over the 150 seconds specified but nothing - no OK or ERROR message. The modem will not respond to any new commands either.

I am monitoring the data lines with an oscilloscope which has verified that there is no data coming out of the modem UART transmit.

Are there any known issues with the BG95-M3?

Is there any way I can see what the modem is doing to further debug this issue?



I am using BG95-M3 also, and i have the same problem when i turn on the gnss module (AT+QGPS=1)
The socket connexion is very instable also.

If gnss module is turned off, all seems ok.

is your GNSS actived also?

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please make sure your apn is correct.

Hi, the apn is correct, it works something like 80% of the time. Even if the apn was incorrect I would expect an ERROR message from the modem. When the problem happens the modem appears totally locked up and will not respond to anything sent via the UART or even if I plug in the USB.

I do not have the GNSS enabled (I think only one can be active at a time).

Can you show me your error log?

You can print the signal strength at that time。

Hi, I don’t know the exact signal strength when the error has occurred but I know the weakest signal strength I have observed is -83dBm.

Hi, can you explain what you mean by error log?

I also have the situation that there is no data returned in the connection at http, and then there is no response when running at + qiact = 1 . I don’t know whether it is the same as your situation. It happened on BG96. Once this happens, need to restart.

are you using hardware flow control on the UART? I had similar problem on UART which stops responding in some conditions. By disabling the UART hardware flow control via RTS/CTS (AT+IFC=0,0 on BG95-M3 side, and related setting on MCU side) the problem disappeared.

Hi Mgigante,

Thanks for the suggestion. I am not using flow control and I am not specifically setting flow control off. I think it is disabled by default but I checked with AT+IFC? and that confirmed flow control off.


I have the same problem with the BG95 sporadically locking up and no longer responding to AT commands. It seems most sensitive to GNSS commands
I’m running firmware BG95M5LAR02A03_01.005.01.005
I have to power cycle the modem to recover
Does anybody have a resolution?


Hi Binks,
It’s been a while since I had this issue, and I can’t remember exactly at what point it was fixed. I am now using firmware version BG95M3LAR02A03_01.014.01.014, I suggest you update the modem firmware. However, you mention GNSS commands and I have come across an issue with .014 where the modem stops responding to AT+QGPSLOC? but it is in fact still working and will report a location when it is determined.


I encountered a similar problem with BG95M3LAR02A03_01.014.01.014. For unknown reasons this version either will suddenly not respond to AT+QGPSLOC? or it will not get a fix after a very long time.

The problems went away after I downgraded the version to BG95M3LAR02A03_01.012.01.012.

Hopefully Quectel can advise if BG95M3LAR02A03_01.014.01.014 is really causing GPS issues.