sim900 not detecting sim card

[fritz-net]

Hello, I have designed a PCB with a sim900 but no matter what I do it is not recognising my sim card. When it boots it says: "+CPIN: NOT INSERTED"

I attached a picture of the schematic, a scope where blue is the status LED and pink the simVDD and a picture of the solderd sim socket because I'm not sure if my pinout is right.

Here is the serial log:

�����
RDY

+CPIN: NOT INSERTED

+CFUN: 1

AAAT
OK

AT+ATE0
ERROR

AT+CPIN?
+CME ERROR: SIM not inserted

I checked the pinout several times cause I often read that this could be the problem and I removed the ESD protection after that I got proper voltage on VDD before there was only short a low level voltage. I also removed the presence 10k pullup and let the pin float.

I hope someone can help and thx for reading

 

[dharithothi]

It seems that something is making your SIM VCC signal forcefully low. It should give 1.8V or 3V as per sim card support. While detecting SIM hardware first GSM engine gives 1.8V Voltage cycle if it is supported by sim then it will work. If SIM dont support 1.8V then GSM engine try 3V cycle to detect SIM card.
In your case neither of them are working. It is good to verify Bottom solderpads of engine. That it is soldered properly on PCB.