so how do i get the code do turn ignition key on and off

Youll need to go to Autozone and have them check it or get your own OBDII code reader. I got one from Harbor Freight pretty cheap.

Vehicles older than 1995 models typically feature the OBD-1 trouble- code system; cars made after 1995 usually have the OBD-2 system. The differences between the two systems are that the older codes contain two digits, while the new codes begin with a letter indicating what system in the engine is malfunctioning, followed by a series of numbers (see Resources). The key "On/Off" method works on older vehicles; the digital dash and jumper-wire methods work for newer vehicles. Read more: http://www.ehow.com/how_7251108_retrieve-car-trouble- codes-equipment.html#ixzz2ag1gJfUk

on the Toyota's of the day you needed to paperclip pins 1+4 on the diagnostic plug~ the 1988 Isuzu Impulse had me fiddlin' around with flashing lights that told me to chage the 02 sensor...which I ignored and later found a nub where an 02 sensor used to be...guess it was late on the combustion situation~ that car was fragile like a subaru~

http://www.troublecodes.net/GM/