GM Hotspot Question

#1

I was wondering if anyone had any experiences with the GM 4G WiFi Hotspots? I believe the cellular portion is embedded with the OnStar module. Is there any wake-up command that would allow it to be turned on and kept on while the car is not running and the key is not in the ignition? I know the remote start abilities are neutered via the BCM but I was hoping that maybe there is a way to keep the WiFi on for longer periods without it being a total PITA.

Thanks!

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#2

It is likely possible but unless someone here knows what the comands are you likely will be looking on your own. The Cellular stuff is done in the VCIM module or the Vehicle to Cellular Interface Module. This likely contains the Onstar module as well. The GM hotspot is likely to be in the same module but I don’t know what anyone else has done in investigating this. Not even sure how you would go about looking at this though.

To reverse engineer how this unit is woken up may require some low level snooping. Such as getting a copy of the code in the unit and reverse engineering the software looking for things.

You MAY get lucky and find a simple code that can be sent to it. But also realize doing so will likely kill your car battery if done for any length of time.

#3

I can think of two ways of making the hotspot power on while car is off. 1. Do a high voltage wake up on GMLAN then send virtual network node wakeup to the ECU’s that is the method I use with my apps to control the vehicle while it is powered off or 2. spoof the power mode state CAN messages coming from the BCM I never tried this approach so it might not work at all. wifi 4g hotspot is built in the onstar module.