07 nissan frontier 4 cylinder truck with the code p1757

Question

its a 4 cylinder 07 nissan frontier

Answer 1

P1757 If the problem is not a wiring issue, it requires replacing the valve body in the transmission.

if there are no metal shaving in the transmission and it is not grinding gears.

a new valve body is anywhere from $900-$1200 and labor is about 3-4 hours 

P0420 is a bad catalytic converter or exhaust leaks. 

p0448 is related to the EVAP system, might be a bad vent control valve