Unable to detect SIM on custom PCB and SIM VCC never goes high

[Deval]

I am using the SLM project with pppd and cmux for Linux on my custom board. I am able to create CMUX and communicate with the nrf 9151 using the CMUX AT port using my custom overlay (which only changes the UART pins). But I am unable to create the pppd because the SIM Card is not detected. 

When I probe the SIM VCC line I always see 0 V. On the nrf9151 DK with the same project I can see that same pin go high and the example project works. 

This is the output I see with the AT commands. 

AT+CFUN=1

OK
AT%XSIM?

%XSIM: 0,9

OK
AT+CEREG?

+CEREG: 0,90

More information. 

AT%SHORTSWVER

%SHORTSWVER: nrf91x1_2.0.2

Do I need to do any additional configuration for the SIM pins? What should I be seeing on all the SIM pins?

[Deval]

Here is the pinout for my device for further context

[Deval]

Additional information

AT+CEREG=5

OK
AT+CFUN=1

OK

+CEREG: 90
AT+CFUN?

+CFUN: 1

OK

[Michal]

Hello,

Are you able to use this SIM card with a DK?

Best regards,

Michal

[Deval]

Yes I have confirmed the SIM works with the DK

[Who_Knew]

I wonder if under the hood, the SIM_1V8 pin is simply a GPIO in structure.  Perhaps it's possible to remove the SIM from the SIM holder and experimentally drive this pin high by our firmware and confirm that the pin is capable of delivering 1.8v.