need help I was able to read and write to this car . Now I get an invalid checksum error . I tried down loading the latest software no luck .Tried to write an old tune to the car still no luck. I tried a stock tune to the car again no luck . tried to contact h.p. tuners ( ticket # 177349 ) but I have not gotten no reply. I am new to hp tuners and was trying to tune trans. and learn this program . so if anybody have any suggestion I would like to hear thanks