Question

P0757 MAZDA - solenoid checks good in the visual & functional test yet still will not shift into 2nd

Answer 1

HI there

This could indicate the computer isn't telling the solenoid to work, or there is a blockage in the valve body causing the issue. Might try a transmission flush to see if it removes any debris. You could also have a wiring issue from the TCM to the solenoid.