Why am I in limp mode after jumpstarting 2004 Titan. At check light on code p072

Try disconnecting the battery and leaving it disconnected while you use a battery charger to charge the battery reconnect the battery erase codes (they should be gone anyway with loss of battery power). Alldata (a company that provide information to aftermarket repair shops does not give a good test procedure that does not include using the dedicated Nissan scan tool. Re check the 10 Amp fuse #14, I don't even see a wiring diagram for the VSS, usually they are at the end of the transmission, one wire will put out a small increasing a/c voltage as you drive the vehicle. Look at http://www.nissanpartszone.com/ or see if Nissan have a parts manual on line so you can see where the Vss is located in relation to the transmission.