SO, for the past month, my 2000 MITSUBISHI GALANT has given me problems.

after work one day i left my lights on on accident...drained my battery.

got my car jumped, and everything was fine...OR SO I THOUGHT.

changed my new battery because the car kept dying out.

two days later, while driving, ANTI-LOCK light comes on, along with SRS LIGHT, and all of a sudden, the car dies out.

a shop tells me a new alternator is needed. so we put a new ALTERNATOR in.

2 days later, the car dies out AGAIN.

a family mechanic looks at it and says its the relay fuse to my battery...

so we disconnected the battery for about 4 days, get a new fuse, and replace it.

as i did a test drive, i realized after all that trouble my bf and i went thru, i realized that when i pressed the gas, the car took long to pick up..and it WOULD NOT SHIFT OUT OF FIRST GEAR...

the family mechanic did a diagnostic with a computer and it came out to:

CODE : p0715

TURBINE/INPUT SHAFT
SPEED SENSOR CIRCUIT

and now i have no clue what to do...

HAS ANYONE EXPERIENCED THIS BEFORE??!
PLEASE PLEASE PLEASE HELP ME AND REPLY ASAP!!!