P1529 and P0715

I have had a 2002 Sonata GLS/LX with 70000 miles on it, for more than a
month now. And I'm in trouble already.When I am driving, the engine
will give a thud and then it will drop automatically to the 3rd gear.
After that, I can only access the 2nd and 3rd gear. I put an OBD
scanner and got 2 errors:
P1529 : Scair Solenoid circuit malfunction
P0715 : Input turbine speed sensor circuit malfunction.(the check
engine light is almost always on). The problem disappears when I
restart the car. I havent' been able to figure out what it means, or
what I should do. Can you tell me what the error could be, and the
lowest cost yet efficient way of getting it repaired? (This is in
Austin Texas)

 

In every case I've seen, P0715/P1529 have arisen due to faulty input speed
sensors. Chances are you just need to replace the input speed sensor.

The cheapest way to repair is to go somewhere and buy an input speed
sensor. It may be a dealer only item. Then install it yourself. It's
partially under the shifter cable. You'll have to remove the air cleaner
and the bolts holding the shift cable bracket so you can slide the cable
out of your way.

 

In every case I've seen, P0715/P1529 have arisen due to faulty input speed
sensors. Chances are you just need to replace the input speed sensor.

The cheapest way to repair is to go somewhere and buy an input speed
sensor. It may be a dealer only item. Then install it yourself. It's
partially under the shifter cable. You'll have to remove the air cleaner
and the bolts holding the shift cable bracket so you can slide the cable
out of your way.