Hi, I seem to have the same problem. I used Kies to update to 4.0.3 and since then the phone has problems whenever it is NOT connected to a charger or USB cable. When there is no cable plugged in the phone still thinks it is charging, and at various intervals between 20 secs and an hour an info box pops up saying "Charging paused. Voltage too high"
I have done a factory reset twice and the problem is still there.
I do not remember the previous version of Android for certain but believe it was Gingerbread. Current baseband version is I9100XXLPQ and kernel is 3.0.15-I9100XXLPQ-CL223505.
I cannot be certain, but the info box seem to pop up more often if the phone is hot, such as when using GPS.
The phone will not turn on if there is no cable plugged in.
Before I did the Kies update the phone was rooted. I did not do anything to remove that, and after the update it was not rooted.
There are a few mentions in other forums of the same thing or something similar happening after doing this update, but none of the suggested solutions have worked for me.
My phone was bought new, unlocked in Finland.
If anyone knows which version of Gingerbread I should try and load, I will have a go at manually going back to Gingerbread. Any other ideas are also welcome!!