That code relates to the transmission:
It's the sensor that sits directly on top of the transmission case.. Easy fix.
This sensor detects the rotation speed of the direct clutch drum.
By comparing the direct clutch speed signal with the vehicle
signal, the ECM detects the shift timing of the
gears and appropriately controls the engine torque and hydraulic
pressure in response to various conditions, thus performing
smooth gear shifting.
DTC No. DTC Detecting Condition Trouble Area
The ECM detects conditions (a), (b), (c), (d), (e) and (f) continuity
for 4 secs. or more.
(2?trip detection logic)
(a) Vehicle speed : 32 km/h (20 mph) or more
(b) 3rd or 4th gear
(c) NC2 < 300 rpm
(d) Park/neutral position switch: OFF
valves and vehicle speed sensor
(f) L position: OFF
Open or short in direct clutch speed sensor circuit
Direct clutch speed sensor
according to this site:
Error code P1705
It's not why your car won't start.