i have had the service engine soon light coming on for awhile.....i took my paperclip and went out and turned the ignition on and stuck paperclip in ports A and B on the data link connector but the car made like a dieseling sound and i took clip out and shut off ignition.....im thinking because i had the ignition already turned on and then used the paper clip your supposed to have it off at first and then use clip....and now i am worried about what i fried in the car.

 

Yes, ignition off, install jumper then turn ignition on. Don't start the engine, just turn it to on. The check engine light will flash the codes, each 3 times, always starting with 12.