P1519 is for the IACV circuit.
P0505 is general idle-control system problem (probably caused by the P1519 problem).
Unplugging the IACV should cause it to almost stall, so that's not OK. But a 2000 Accord isn't supposed to have an FITV...?? There IS a coolant hose connected under the throttlebody, but it's not an FITV.
You should probably go over the whole idle control system, I suspect that with a non-working IACV someone may have compensated by adjusting the idle screw or something.
'05 Saab 9²x aero (RIP)
'09 Saab 9³ss
'10 Saab 9³sc
my kids have Civics