Have you tried to Format the Ext Stoage,
Someone ever told me that on occasion the GPS tries to connect to the server that was stored in memory, and for this reason, de GPRS Status, cannot be activated.
This works for me. hope works for you.
Sorry for my english, not my first.
This is only if you already connectd de DIN 1 to +12V and set an APN on GPRS CONTEXT .