Ever since the first versions of my rSAP app, I've been haunted by the problem that for some users the phone does not reconnect to the mobile network after an rSAP connection. I still don't have any idea why this happens. My best guess is that it is an issue with the SIM card.
Many times the problem can be fixed by activating/deactivating airplane mode, so I created a plugin that does this automatically after the end of an rSAP connection. Alternatively you can also have the RIL demon be killed, which is by far more "rude" but may help in cases where the airplane mode fails. Needless to say that both operations need root access, airplane mode is restricted since Android 4.2 for whatever reason.
At the first disconnect from your car after installing the plugin you will get the Superuser request. Be sure to watch for this and allow it permanently!
Please use/create new threads to report problems.