[Ovmsdev] Cannot reset simcom stuck in PoweringOn state without removing module power

Craig Leres leres at xse.com
Sun Jan 5 12:16:28 HKT 2020

The simcom on one of my modules wedged today and had some time to poke 
at it. When I turn on simcom debugging I see "AT" commands once a second:

     D (1199981) simcom: tx scmd ch=0 len=4   : AT
     D (1200981) simcom: tx scmd ch=0 len=4   : AT

but no responses.

I wanted to see if I could talk to the simcom via the usb connector on 
the modem card so I sacrificed a micro usb cable and hacked the molded 
end off so I could plug it in without detaching the modem board from the 
main board (see attached).

Next I spent a few minutes with a spare module looking for a windows 10 
driver. The sim5360 (rar) archive from techship.com didn't work but the 
windows 8 zip file from here did:


I ended up with four com ports (at, nema, diagnostic, and audio) and was 
able to talk to the spare modem.

Then I went out to plug into the simcom in the car. The first thing I 
noticed was that the blue led on the modem board is not lit and (as 
expected) I got nothing from the at com port.

For completeness I tried rebooting the module but it help.

I now believe wedging the simcom involves running the car for a short 
amount of time. In this particular case I moved the car out of the 
garage to make room for some work on my other car. An hour later I moved 
it back. The run time was 1-2 minutes each time. A bit later when I 
tested Mark's new ios app I noticed that the car was not reporting a 

I looked at the simcom docs a bit and it's too bad the simcom RESET pin 
isn't connected to a pio pin.

It'll be a couple of days before I'll need the gps to work in case there 
are ideas of what can be done via software to wake up the simcom. I 
might trying add a simcom command to set PWKEY to an arbitrary state to 
see if holding it low for more than one second does anything.

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