Default how to diagnose modem?

I took my phone for a swim (oops!) Was sure it was a total loss but eventually after being salted and riced it was working again despite some screen flickering which has also now stopped but ive noticed it hasnt touched a H hsdpa network, it is only connecting to G gprs and E edge networks. Does anybody know a way I can test this? Or any tricks?
Samsung Galaxy Note II
ARHD23/mannyvinneys240dpi/E-Team Note3/WanamXposed
TWRP (htttp://goo.gl/aNc64G)
AdAway 02-28-14 (Http://goo.gl/0DZkTd)


HTC Desire HD / Android Revolution 6.4 (recycled)
Sony Ericsson Satio (recycled)
Nokia 5800 Xpress Music (recycled)
Sony Ericsson K800i (unknown)
Nokia n95 8gb Music edition (washed/binned)
Nokia 6280 (destroyed/binned)